This is a really good point that I hadn't considered before. It's facebook all over again — selling your own content back to you. Repo owners should be at least compensated when their code gets used. That would be an incredible market.
I for one welcome our new CEO (Copilot Engine Optimization) overlords.
Jokes aside that will likely cause GitHub to be filled with lots of low quality repos (even AI generated, oh the irony!), to trick Copilot into using their code.
Hasn't this already been the case since GitHub became a CV boost.
I think the bigger problem is that it will almost certainly lead to a proliferation of giant snippet spam repositories.