Bees? Natures little snacks?

Games as a Service wasn’t even the fatal flaw here. Brawlhalla is another platform fighter that is doing just fine off that model. The dev team for MultiVersus just couldn’t handle the project, for one reason or another.
A lot of speculation on the specifics of what went wrong, plenty of players looking for who to blame, but there will probably never be any reliable or concrete info on what exactly happened.

“Probably”? I think the only advertisement I’ve ever seen from Valve was for Half Life: Alyx when it came out a few years ago. Not exactly brainwashing kids
Additionally, kids are not the largest group on steam. According to Statistica’s Consumer Insights Global Survey, the majority of users are 30-39, with the next largest group being 20-29 https://www.statista.com/forecasts/1242344/steam-us-user-share-by-age
I’d say Deep Rock Galactic has a lot of the same appeal, and thas doing pretty well. Though it also made the bold and controversial decision of actually innovating and creating something new, rather than sticking as close to the original as possible.