While Linux might not be as unstable as everyone makes it out to be, your argument doesn’t support that at all. The point is Valve maintains Proton so that everyone and their mum doesn’t need to maintain their own Linux fork that’ll bitrot. Without an entity maintaining Proton it could stop working in a few months for all we know.

Yes, and nobody knew how to deploy or use Linux applications until Docker came along and saved us all.

I for one knew how to deploy Linux applications long before Docker but know nothing about the GPU/graphics stack on Linux which is crucial to game devs, and FWIW I ran into graphics problems when I tried Ubuntu Desktop (yeah, just the vanilla Desktop, not gaming) on my Nvidia GPU last year, so again your snarky response contains no relevant info at all.

Better controller support, especially vibration, and higher frame rates count as measures in my book. Have you tried it?

Yes absolutely. Proton is a great product. But underneath, it's still Linux. So saying 'Linux support is terrible, Proton is better' makes absolutely zero sense.