In principle it sounds like a good idea but I am skeptical to be honest. I think that even though low-quality proposals get rejected, we may actually be incentivising a high volume of content to read and go through for no actual gain. It could create actually the opposite effect of wanting to propose or read proposals.
On the other hand, I think that every RIP that gets approved it’s actually changes to the protocol, time from the devs, etc so we may want to put a limit on the number of possible RIPs per month or period of time? This proposal may actually incentivise a huge amount of changes.
Lastly i like the idea of incentivising people with successful RIPs with more voting power for future RFCs (not sure if this is possible) than money. So for example you could accumulate badges every time your RIP gets implemented and that give you more power to vote in others RFC. This way those accumulating the badges can be recognised by the community as active and valued members and you start having a reputation. If it gets too big, badges could be reset every agreed time.
I hope all this make sense 