Ok so the thing with Steve honestly, and i been doing ALOT of thinking on this (and laughing at the few people who got rick rolled by the steve leaker)
He could honestly get in on a couple of justifications. Minecraft is a large game itself and its honestly the best lego video game in existance. That aside the arguements I figured to come up with for him can be easily shot down as well.
1. Steve as an Indie rep- Minecraft is one of the best selling independently made video games of all time, and the most successful. That said at the time the roster was made Minecraft was in the decline. Still is to be frank. Although Fortnite was yet to really be a thing back in 2016-2017, the indie darlings at the time were objectively Shovel Knight (whos currently in assist Purgatory) and Shantae (whos creators are lizard speaking on the topic of her in smash). Steve would be a decent fill for the role but theres alot better
2. Steve as a PC Rep- Minecraft did of course start out as a pc only game did it not, with it coming to consoles after it had already taken off. The problem with this front though is when you think PC youre not exactly thinking minecraft are you. chances are youre thinking of Valve and Steam, and Honestly a Valve Character to represent PC Gaming just makes that much more sense (my personal pick there would be The Heavy from TF2) as without Steam as a marketplace, thered be no PC Master Race.
3. Steve as a Microsoft Representative- Microsoft currently own minecraft and it is one of their current best selling titles, but if microsoft did want to get into smash (assuming nintendo would work with a DIRECT COMPETITOR), Phil Spencer already has his favorite picked out being Banjo who has the seniority with nintendo, and itd make alot more sense to have Marcus Fenix or Master Chief who are far more synonymous with the Xbox brand as a representative over Steve as well.
4 Steve as a WTF choice- People bring up every smash game has a WTF character since the beginning (64 its Ness and Falcon, Melee its Game and Watch, and so on). Trouble is that the WTF oddball choice has always been a first party nintendo character. All of them are and I highly doubt that tradition would be broken for a character that wasnt born in the house of the plumber. Honestly for this I'd more expect to see Stanley the friggin Bugman than Steve because Stanley was in a first party nintendo game at least.
Anyway believe what you want just dont get RickRoll'd by obvious fakers again.