Can someone do it? Technically, yes.

You need a FUCKTON of funding. Hire a large team, build a competitor app from scratch.

You can't just build a metropolis and it expect it to float. Undercut them on pricing. Provide strong publishing support and metrics out of the gate. Advertise partner games while on game load. Provide strong anti-cheat without kernel fuckery. Provide backend server support in the vein of roblox. Wire in clauses that server-based games either run on your backend, or escrow encrypted backend code to you. On long-term abandonment, you reserve the right to host or release the backend code. Players will come rally around you for supporting stop-killing games, and if you pull it off right, you might even make the creators happy.

The best they can do is drop the take to match your price and provide the same services you provide.

The tricky part: You need to keep them from buying you. Your venture needs to not GAF that it's going to take forever to return on that investment. You can tit-for-tat features in an AI world, but staying a step ahead of them is going to require deep pockets that are just content to eat some of their pi and sustain.