Whether or not you have a point here is meaningless because I was referring to past tense. "Before Snake was announced for Brawl" is the major point. Context matters...
There is a difference in behavior between "lack of interest" and "actively trying to define the debate." I have experience with this debating politics. If you truly had a lack of interest in first-party inclusions, you would've saw this thread, knew what it was gonna be about and said "**** it, in the spirit of the OP I'll let them have their talks" but you didn't. No good deed goes unpunished. Do you think that maybe this thread was made with specifically you (and maybe tehponycorn) in mind?
You say you don't generalize but you do exactly that with Nintendo picks. "They wouldn't generate hype while third-parties will..." Imagine if Smash wasn't made by Nintendo from the onset and it was some other software developer (like say, Bandai Namco). The intention was always to include ANY video game IP they could get the license to and that put every company on the table, no console exclusives. That would mean Nintendo was a "third-party" pick just as much as everyone else. What do you think would happen? Nintendo would dominate discussion anyways since they are the company with both the history AND the IP quantity to make it happen. The only people who would complain are people who weren't interested in Nintendo to begin with. You see how the tone shifts when you stop thinking of it as "Nintendo vs. everyone else." And you're still trying to gatekeep by saying we should advocate for the newer stuff if we should be taken seriously. The "relevency" argument mattered as much as "Banjo vs. Steve," and how did that work out? Oh, but I guess it's different 'cause it's third-party and that means...... different or something.
You come off as someone who would flip just by me mentioning it, but I'm gonna anyways. "Objective art analysis" is a thing. That doesn't mean subjective interpretations are invalid, but what the art actually IS matters just as much, and what the art is goes against what the author says it is or intended it to be. One of the most infamous examples is George Lucas' insistence that Star Wars was "meant for kids," even though the original movies and even some of the newer stuff has elements not suitable for children. Lucas says one thing about the franchise but the actual content says another. Likewise, it doesn't matter if Sakurai or anyone at Nintendo saying it's a "general gaming crossover," what matters is the actual content, and Smash is still a Nintendo crossover with several guests even if every DLC for this game ends up third-party...
Your pre-Snake commentary didn't really land because I didn't find it phrased super well, so I didn't really get what you were going for. You were referring to past tense in regards to before Snake and present tense in regards to the IPs not currently in Smash unless I've misunderstood and you were seriously commenting upon Snake's inclusion as the problem because "tons of first party IPs didn't get their shot or included" with him as the target of that scorn.
I originally commented in this thread (before yesterday) as ways of trying more active engagement with the ideas at hand and trying to start more of a discussion that ended up sort of fizzing out. I wanted to have a more serious discussion with people on this topic because I do find it interesting. I admit I reacted poorly when I saw the Plant/Fire Emblem bashing, which puts me in mind of the worst people of the community. The people who criticize them typically are the same ones who criticize characters that aren't their preferred, and I'm just used to pushing back against those types. There's admittedly some frustration I have personally with some people who constantly feel the need to keep calling Smash a "Nintendo crossover", and again, I'll admit that's a bias I was wrong to let dictate so much of my thought process. My main disconnect is the whole "once in a lifetime to have this many IPs and companies cross over." Maybe this is just who I am, but that dictates a huge amount of my decision making, "Once in a lifetime" means you should absolutely take it and do as much as you can with it before it's gone, and just the achievement of Sakurai being able to get almost every major Japanese IP across all of gaming together in the sort of goal I just think you have to kind of respect.
But my point is that your thread bases itself on the pride of first parties and is pushing for their continued inclusion. Advocating for new stuff seems like the best route forward to that because at least Nintendo would have more of an interest in those titles and characters. Simply put, Nintendo isn't going to go against their own financial self interests. If they see enough fan demand in the right spots, they'll go after a character. If they see a wide enough consumer base to appeal to with a new character, they'll go after that one. Picking less relevant characters with small fan bases and limited appeal isn't an economically smart or sustainable model. Again, Nintendo will always be a business first, good guy company second. That's not to say there are no options, but notice which ones manage to even dominate the Nintendo polls these days. Brand new and continually successful fighters. King K. Rool was rather an outlier in that regard. Inkling was a huge part of Smash 4 DLC's speculation. The biggest first party winners for Ultimate were the likes of Ashley (Nintendo Badge Arcade promotions), Bandanna Dee (new Kirby character with the spotlight), Waluigi (appears in every single Mario spinoff more or less and has never gone away), Rex/Pyra (most recent Xenoblade game), and Ridley (a mainstay of Metroid that continues to appear). Isaac was the only one really playing from a position of disadvantage due to the lack of new Golden Sun. People tend to still stick more with the newer/continually relevant characters because they get to interact with them more and don't have to revisit older titles that may be less available. It's in Nintendo's best interest to promote those titles and those characters because they will continue using them if they're making first party choices. Relevancy can only be superseded by fan demand, and really Geno and Isaac compose the entirety of characters left with enough pull to make that climb out. It's a matter of practicality to getting more first parties in. Either make massive fan demand or support more relevant/recent picks that are more popular in general. That's the best way forward when Nintendo is steering the newcomer picks especially and there is no sudden Sakurai surprise to be had. Show them first parties are going to be worth their effort and can sell as individual DLC.
There's some degree of objectivity in art analysis, but it varies wildly from medium to medium and depends largely upon the school of thought you subscribe to in said analysis. Death of the author is but one of those many schools you have to decide if you will personally use in your criticism. It's not a catch all that literally applies to every situation. Lucas wanting Star Wars to be about kids informs you a great deal about the films and the series as a whole, and gives you tons of possible ways to explore the films. This becomes even more critical in analyzing authors like Leo Tolstoy whose entire life so heavily effected the books he wrote that they are largely autobiographical in many instances with specific characters. To take a "death of the author" approach deprives you of so many readings, analyses, and arguably hugely important context.
A further issue with applying death of the author here is that due to the continued prevalence of third parties, Ultimate's content would still communicate it as a crossover of video games with a large amount of Nintendo content. Would an outside observer think of these third parties as "guests" or just standard elements of the game? And does the body of people in the public defining Smash as "a video gaming crossover" based upon the content they see in the game not matter in this context? I don't think "death of the author" really gets you very far here in terms of trying to turn back the title to a "Nintendo crossover" when that interpretation even based upon what is in Ultimate is already contentious at best (This also assumes you can use a theory created on the basis on analyzing literature so broadly in analyzing a video game, which is such a wildly different medium that I just don't think its appropriate to use it in the same way. Video games need more legitimate criticism as a whole and could use a wide variety of definitions in that criticism IMO).