@NE0N: Most of your post is missing the forest for the trees. Your trying to hard to look at little details and not the big picture of why a game sell well. I'm not going to talk much about the post since it's not worth it to go though every detail, but I'm going to point out examples where your idea strays. Again, the idea is that "The characters are the main reason why Smash is doing well." If this is true, that would mean the characters are the main reason video games sell. If the character is the main determinate of success, than I should see characters push products and not the game itself. So, for example, if the Nintendo characters push Smash, then likewise, I should see Mickey Mouse games sell better than Mario as Mickey Mouse is a more popular character.
Mickey Mouse games by sales(estimate)
As you can see, sales are kind of low. Mario games do far better. If characters push products, then why is Mickey Mouse games selling less than Mario games? What this mean is that the products itself is the reason something sells and not the game itself. A better example.
No Sonic games do that well anymore, compared to games with Mario in them. The Sonic and Sega games sell pretty similarly to regular Sonic games, and really the only thing that still causes the Sonic games to be successful is brand recognition. It's not surprising Sega crossovers don't do any better than Sonic games, Sonic (and his dumb friends) are really the only highly marketable one out of all those characters they use. But Sonic isn't in traditional fighters, plus his games are fairly accessible, so I don't quite know why he was brought up...
This prove my point. Sonic 1 sold about 4 million and Sonic 2 sold 6 (about). Yet, Sonic games aren't doing as well. If the character is the reason a product sells, then sales should be better. Sonic games are sold on all three major systems and PCs. No longer does a customer have to by a Sega system to get Sonic. Using this idea that characters sell products, then I would expect to see sales go up. Instead, sales go down. This means the reason for Sonic sales has very little to do with the character. Likewise, Mario Sunshine and Galazy sold less than 64, and 64 sold less than the originals. But NSMB sells more. Why is there such inconsistency. The character, Mario, is the same in all of those games.
Mario sales estimates. Look at the inconsistency. If Mario is the reason people buy the product, why did Mario go from 40 million to 6 (Sunshine). Let's look at Mario Golf. It sold about 1.5 million. Why is it not selling as well as Mario Kart? Mario is on the box for both. So, by your logic, then the games should do about the same.
Let's look at Golf games. The besting selling game is called "Golf." The next best selling ones are Hot Shots Golf. While Mario is up there, he is beaten out by a game with no memorable characters.
I'm not saying the style of gameplay doesn't contribute to the success of the game, the marketability of the characters just contribute more. Unlike Marvel, Smash appeals to the core audience of the characters included, gamers. People are most familiar with Spider-Man from his movies or his comics, that's why he would do better than Mario would in movie or comic book sales. People are most familiar with Mario from games, that's where his audience lies, which is why games with him (even if they include many other characters - as long as Mario is clearly promoted in the game) sell well. The same could apply to the other big names in Smash, but to a lesser extent. Mario got to that point through quality games, sure, and he still has quality games (among weaker ones), but now he can get by on brand recognition. When other characters like Link, Pikachu, Kirby, etc. are also included, that only aggregates more audiences together into the same interest. By now the Smash name itself also has brand recognition, which it got partially through the gameplay, yeah, of course, but the thing that caused the majority of the interest in Smash in the first place were the characters included in it, that much is obvious.
Here is why what your saying is wrong. What you are saying is
Marketing is the reason why products sell. As an up and coming investor, this makes me laugh. Marketing doesn't sell products. Products sell themselves. Given, it's easier to sell a products with better marketing because you get the name out. But if your selling a bad products, no amount of marketing in the world can save you. This is why sales are inconsistent. The reason why Smash does well is because the product is strong. It is easy to get into in a genre that focuses on more difficult gameplay.
Go read the Blue Ocean Strategy.
That's not entirely true. Most series have fluctuated. The second Zelda game on a system never sells as well as the first. Overtime, starting with OoT, MM sold worse, then WW sold better than MM, TP did better than WW (though not the Gamecube version), and SS didn't do as well as TP. The only consistency is that the first Zelda on the system sells better (as do most series) because it has a longer time on the market and usually is on the market when the console is at its peak, not afterwards. Corruption did better than Echoes, there has been no consistent decline in Metroid either. Awakening has been the best selling FE in a long time, AC is doing ridiculously in Japan, better than ever before, Galaxy 1 & 2 both sold better than Sunshine (Galaxy isn't in the same series as Brawl, they're not comparable), DKCR did better than all previous DK games since the original DKC, Kirby's as profitable as it ever was, very few major Nintendo series are in chronic unavoidable decline. The next Zelda (not the WW remake) and Metroid games will almost definitely sell better than SS and Other M, as long as the Wii U has at least a decent player base, and the games arrive in the next few years, because the system also matters.
This paragraph is where your argument falls apart. There are so many consistent elements that can't be explained in your current context. The other question I have is how is any of these relevant. Are you trying to say your argument is right because Nintendo series are not in decline (which they are. It doesn't take a rocket scientist to see that old sales are higher than new ones). Even then, how does this help you? What point are you trying to get across? This is probably why you shouldn't split up a paragraph into 4-5 points.
The characters are obviously moving the game. They aren't the only thing moving the game, that much is true, the gameplay does play not an insignificant part, but the majority is the characters. Do you really mean to say that if Smash Bros had only ever had original fighters, it would be in the same position it is today? That's just totally unrealistic.
There is no way to prove this, so what your saying is faulty anyway.
Smash isn't the only accessible game series in the world, yet it sells better than 90% of other "accessible" series, if not more. Plus, there are many "accessible" game series that sell very poorly, even if they are easy to understand and play proficiently. How are people even going to be drawn to accessibility in a game they haven't played before? They know Mario, they know Link, they know Pikachu, they know some other character, they like those games, they buy Smash. Sure that doesn't apply to every person who's bought Smash, but the majority.
What are these other "accessible" games. You never say.
Another thing: You don't give any evidence on why you are right. If what you are saying is true, then it shouldn't be hard to get some facts.