I think this is a fair and normal reaction to AI slop. Alot of work though. I think OSS projects are at serious risk of implosion due to the vigilance required which honestly may end up being a fool's errand anyway.
But maybe we are thinking about it backward. Have you ever wondered why there is so much "free software"? Beware of strangers bearing gifts.
I have always wondered and been suspicious of people who are so eager for you to use their software. Which isnt to say OSS isnt high quality. Im just saying that maybe when people are pushing free software on you they are kind of in it for themselves.
As for whats next, me personally, last year I pulled all my personal repos about 80 of them off of bitbucket and self host that all now. I think OSS projects should setup a paywall and charge money to create PRs.
Like 10-100 bucks per PR to cover the cost of the extra vigilance. Also I could see migrations away from github, to AI free dependency hosting or something like that. Its an interesting challenge. But its not insurmountable.
Either paywall OSS projects or take them off the interwebs. Also one option the OP didnt explore I dont think is forking and freezing the dependencies. Huge maintenance burden, but its better than source corruption.
Also use fewer dependencies. Maybe set a limit of 5.