https://www.protondb.com/dashboard

> Top 10 - 20% Platinum - 30% Gold - 10% Silver - 30% Bronze - 10% Borked

I'd probably say at least Gold is "reliably click and play without fiddling", so probably we're around 20-50% there right now, if we consider the top 10 games on Steam. Once you start considering top 100 or top 1000, it starts to look a lot better. But still, mainstream games are lagging seemingly.