escrow is a more complex system, and there are multiple possible implementations, but the nice thing is you can skip it and get the same results.
let's assume for a second that the repo owner spends time on PR review, and that time needs to be reimbursed. let's also assume that the person pushing a PR expects some sort of bounty. then as long as the review price is less than bounty price, there's no need for escrow. the pushing party goes out on a limb paying the reviewer to merge their PR, but also expects (rightly or not) to be remunerated for solving the bounty. whether they really did solve it is in the remit of the bounty originator, who might or might not be part of the group controlling the repository. if there's escrow, then the bounty giver probably has to be part of that group. not having escrow allows for crowd funding by interests outside of the repo controlling party.
escrow is only usefully different in a situation when there is no bounty, you want to push code, and then you want to say "ok, here's some money, and here's a PR, either accept the PR and give me money or don't accept it and take my money" as a means of skipping the line or getting a shot at pushing in the first place. however, at that point two things are apparent: 1. you expect the reviewer to do work required to implement your desired changes for free and 2. this might start getting abused, with PRs getting rejected (to gain money) but then modified / refactored versions of this code being pushed via commits or from another user who is the repo owner's puppet (refactoring code is becoming super cheap due to AI). so that degenerates escrow-to-push into a scam.
there are more considerations like that in the article I linked to. I agree that an economy around FOSS pushing would be desirable. it also doesn't preclude free-as-in-money contributions - there are at least two mechanisms that would allow it: 1. you get sponsored by someone who sees your talent (either gives you money to push, or they have push access to that repo and can hand it out free) 2. you create a fork that becomes so good and valuable that upstream pulls from you for free
ultimately becoming a respected developer with free push access to contended repositories should be something that you can monetize to some extent that's purely within your remit, and it would greatly reduce unserious bullshit coming from third parties (especially all those weird hardware developers) and make it easier to be a FOSS dev.