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.
Yep, it’s from back in the day before Proton, where Dx10 support was spotty at best. I know it probably wasn’t as simple as “3D = broken, 2D = fine”, but I think generally 3D games tended to use more exotic Dx10 features.