Now, we have larger projects where it is rare for one people to have a complete understanding, and the main value is a person to reviewing patches and bugs to make sure the changes align with the larger goals/path for the project. There is little incentive for a maintainer to do this, aside from wanting to limit forks.
Paying for that review might be the way to keep this whole model sustainable.
“Here is my pr I attach x$ payable when it is merged” and allow me to add $ to other prs.
I have been waiting year + for multiple feature in some projects that have open prs and for one I would easily bid 100-200$