Risewild, I don't think you realize that most of the properties in Multiversus are pretty old lmao THey don't have stuff kids are watching on tv, they have a lot of Nostalgia pandering.
That's the whole point. They are trying to get kids into those old properties and make them relevant again.
Also, they are mixing old stuff that kids don't care about with old stuff kids still care about, like Batman and the Justice League. Kids love Batman, Superman and Wonder Woman even today.
Want an adult fighting game with Batman? Play the Injustice games. Want a kid fighting game with Batman? Play Multiversus.
Adventure Time started 12 years ago and only stopped 4 years ago, so teenagers today still grew up watching it.
Steven Universe started 9 years ago and only ended 2 years ago, same shtick as AT.
That's what I mean with them aiming to addict kids and manchilds. They mixed both old and by now irrelevant IPs with more recent ones that are aimed at (now) early/mid teens and ones that have always been popular (DC Superheroes).
And then we have Lebron, that's someone adults and kids admire today, and many kids wish they could become the next Lebron James.