The shift has been spawned in part by policy changes at Roblox. A December update to the service lets players easily transfer game ownership.

The creator of “Blue Lock: Rivals” thought kids on Roblox might like a soccer video game with an anime vibe. It sold a few months later for more than $3 million. The 19-year-old, who asked that his ...

Roblox modernizes game ownership rules, and teenage developers are cashing in on their creations, earning millions while still in school.