But the only ways to give money for VRChat is the subscription for extra avatar bookmarks and a fancy nameplate. And from what I understand, the deeper into it people get, the more likely they are to stick to one avatar.

This is a pretty good deal for the users, but it's not going to pay for a Meta quantity of developers.

Yet if they put in all the mobile money extraction mechanisms into it, why would people choose Meta's product over VRChat?

Meta will be taking approximately 50% of all sales on their metaverse platform IIRC.

Seems a bit much.