That would be several absolutely radical paradigm shifts in how we use packages; depending on how big Y is some companies I know would blow through that in a single parallel CI run. They slice up their (enormous) test suite in over 100 slices and run each slice in a separate docker container. I also wonder how pricing will be determined. As an extreme example, that colors.js package that was in the news a few months ago because the dev intentionally broke it would not be worth $49 even when it did work. It literally only added terminal coloring codes to strings. JS is kinda notorious for having many tiny packages of course, but even larger pieces of software are extremely difficult to price. How much should postgres cost for example?
Finally, how will they determine which of the devs get how much each? Does it all go to the repo owner or will there be a pro-rata split over each contributor? Both will do some interesting things to the "FOSS community spirit", imagine having a useful PR refused solely because the repo owner doesn't want to share the income with others. I usually don't even bother asking for attribution when making a PR to an open source project, but if I knew the maintainers were getting an income from it then suddenly working for free seems a whole lot less attractive.