Will you please actually read the quote rather than quoting an inorrect interpretation. The quote is:
"given enough eyeballs, all bugs are shallow"
It means that once a bug is found, it is shallow, i.e. quick and easy to solve for someone. It doesn't and never did mean that all bugs will be found.
Actually, it's unfortunate, but I think he did mean that:
Given a large enough beta-tester and co-developer base, almost every problem will be characterized quickly and the fix will be obvious to someone.
That's his longer version of the same slogan - literally the next sentence in the essay.
It's possible to read that as meaning that every problem —once it's been found— will be fixed quickly and relatively easily, but Occam's razor says that we should understand discovery of the problem to be implicit in this statement.
But... you are right to say that FOSS is far better at fixing known bugs than proprietary software. By the late '90s, I was so sick of having my professional reputation as a systems software developer tarnished by bugs, poor quality and stupid release cycles that I stopped supporting Windows entirely. Dropped the entire proprietary ecosystem and moved to Linux and FOSS. I can't say it's been perfect, but I've slept way better since then.