Basically, the reason Steve is even a factor in this thread at all is because there was one "leaker" who continued to insist beyond all rationality that Steve was going to be in the game. First, it was DEFINITELY main cast. Then, it was DEFINITELY "Minecraft will have a stage but not be a playable character". Then it was "oh, he's actually DLC" and so on and so forth. Every time a new thing came out to debunk his "rumors", he changed his story to move the goalposts.
Yet somehow, the rumors continue to persist because that leaker was so prolific and so prone to running his mouth that his bullshit essentially sank into the public consciousness surrounding the game.
Is Minecraft popular? Absolutely. But that doesn't mean it's got a super high chance of being in the game. And honestly, it shouldn't be the criteria. "This character is super popular" would just open the doors to a generic Fortnite character or the PUBG guy or Thanos being in Smash just because they're popular, rather than because they add something meaningful to the roster from a gameplay perspective.