> make a contributor pay for the review of its PR, even a small fee

I agree!

The problem is obviously a resource allocation one. Economics solves problems like that.

To make the system viable, you need something like the free-to-play games use (shudder).

Offer a choice: user’s time and attention or money.

(This addresses the issue of excluding low-resource contributors, which we might care about for equity or because that was us when we were young.)

As an idea on the money front, you could require the contributor to pay for the tokens needed to review their PR! Maybe even let simple models review simple PRs or advanced models decide which model is needed to do the actual review.

I don’t know how the humans can contribute their time and attention effectively, but maybe we can figure that out.

We've already had solutions like this in the past, pre AI. Bounty escrow companies that pay FOSS contributors per PR. They've mostly all failed or pivoted. Why?