You ignore the reality though that even though it might be "epics job" to support Linux, it's still the user's problem right now if you want to play Fall Guys with your friends.

And you can't just say "playing Fall Guys is not exactly necessary". Social connections are very important to humans, being one of a group to not be able to participate in a shared activity can be socially isolating. Of course that's a completely different topic you could argue about if it should be like this, but you can only dismiss it as not necessary for yourself, not as not necessary in general, for others.

If you use Windows, it works immediately, if you use Linux, you have to spend the time and do whatever that guy did. This is a very real cost for the user, time is one of the most precious things we have.

Of course you can argue about if it is worth it, but in the end people assign different value to things. If playing Fall Guys is very important to someone and it takes more time to do on Linux than on Windows, then Linux loses value. And this situation is not a single instance. People mostly only do what is the best for them in particular, and using less time to do the things they want to do is a prime example for this.

You do realize how much money Microsoft spends to make games work well on Windows, right? It is absolutely the responsibility of the OS to ensure smooth experience across many apps and services. This attitude right here is why Linux plays second fiddle to Windows still.