The HL3 memes don't even seem fair to use anymore. I don't even want to un-seriously make joke fun of them at this point. They are just genuinely doing so much for the community.
Targeting Wine/Proton is the best of both worlds for everyone. Developers need to Just™ not use a few footguns that they mostly don't have reasons to touch anyway, and otherwise they don't need to change anything, while consumers get a game on that works just as well on Linux as on Windows.
Wine meanwhile works perfectly with 80+% of games, and those 20% that don't are all newer stuff or stuff that's never going to get a Linux version short of the Linux desktop actually getting of the ground.
Also Microsoft Games Studios owns enough studios to make an impact.
Also Proton means zero game studios have to care Steam OS exists, they target Windows, use Visual Studio, and Valve is the one that has to make the needful if they care.
The same studios might even be using game engines that support GNU/Linux, yet letting Valve do the work is much more appealing.