It's Linux's failure that one of the world's biggest corporations outspent it on marketing by orders of magnitude? You can sell crap like hotcakes with enough money and advertising minds. Yours isn't really an argument for Linux APIs being any worse or better quality.

> Linux adopted Win32 because it actually worked.

WINE would have been invented one way or another because enough people would have wanted to run Windows programs on Linux in a world where Linux had dominant market share. For Pete's sake, there are Commodore 64 emulators for Linux in a world where that system has been dead for decades. It has nothing to do with what "works" or not. WINE and Proton are developed as actively as they are today because Microslop has been able to market so effectively to convince average joes and businesss leaders to buy their crappy OS. This has nothing to do with the quality of APIs.

> They could have simply invented a better API that didn't suck.

Is there ever a situation where this statement isn't true? Everything built in software can be seen as sucking, and all software could have been written better the first time around.

> Linux adopted Win32 because it actually worked.

Completely untrue - Linux "adopted" Win32 because the majority of video games are written for Windows (and thus Win32).

They could not have invented a better API because the entire reason Proton exists is because developers don't build native Linux games.

> It is a hilarious and catastrophic failure of Linux userspace that the best API for running games on Linux is Win32

Studios don't target Linux, they target Windows and sometimes Mac.

Imagine if Flappy Bird targeted only iPhone, because there were only 50,000,000 Android users in the world (hardly worth supporting). Then Android creates an iPhone runtime on Android so people can play Flappy Bird on it, and you conclude "iPhone actually worked, this is evidence that Android is a hilarious and catastrophic failure."