Has it really been that long? Apparently so. Valve originally announced their rebranding of Steam Play with Proton back on August 21st, 2018. Seems like a good time for a quick reflection being halfway to a decade old now with the tech that gave rise to the Steam Deck.
The results were fine, but the work to get there was quite bad quite often.
UX polish is one of those things that just isn’t as fun to do, and isn’t as rewarding either. So pumping a bunch of money into it is going to go a long way towards making all the other hard work come out better.