In my opinion, this is not a needed feature. As some of the previous posts stated, plugins aren’t fundamentals of any game. Because of their nature plugins don’t do the impossible as well, they are just nice tools which saves everyone time. However I personally don’t know any creators who would be willing to give up on some of their profits repeatedly in a percentage for a plugin.
Bigger studios would make their own internal plugins so even if this was released it’s really hard to tell who would be the customers of a such plugin sold with this method. Probably only people who would be using a such plugin would be the ones in the free tier, which would be less revenue for plugin creators at the end.
Because of all these reasons I don’t think that this would be a good method of making sure that plugin creators make a good amount of money for their plugins.
Subscriptions would maybe make more sense but to be honest I don’t know if this would be popular in Roblox or not. However subscriptions would still be better as an option, especially if plugin creators are also encouraged to release single purchase versions (like Office 2021 relasing alongside a subscription which is Microsoft 365) of their plugins, which they would not maintain on a regular basis unlike their subscription plugins.