I guess because it gets all the games, to the point Valve needs to create a Linux distribution that pretends to be Windows to be able to sell any meaningfull games to GNU/Linux folks, not even Android/NDK games get ported over.
Yeah it's insane how downplayed windows is in some tech circles. I personally don't even like it, but that's mainly because of a skill issue on my part (I don't know how to use it well). Yet it is very clearly not a toy, and in some ways it's way more powerful than Linux due to things like active directory and everything. I wouldn't run a random server on it but that's completely irrelevant to it being a toy or not.
In reality as you said tons of effort are spent exactly trying to make Linux good at the things windows has been good at for 30 years. But there's that weird dissonance that makes people think that windows is inferior to Linux on a technical level just because it's inferior on a software license/freedom level. The two are completely unrelated. The funniest thing is people who argue that the Linux kernel is just the future compared to the "antiquated" NT kernel (lol, lmao)
