They may well be lying about their reasons/justifications, I don't have any way to know one way or the other.
This just isn't a new thing. Companies fave been blaming the high cost of supporting the relatively small number of users on an "alternative" OS for a very long time. Unfortunately, I think that as long as desktop Linux is in the single or low double digits of percentage of users, this is something we're going to keep hearing.
A company is unlikely to do a thing if it's cheaper to not do the thing.
Yeah. I'm not sure that this has changed much.
I suspect that was a large part of what drove the excitement for something like Valve's Proton. It was supposed to make it easier for studios to make games available across platforms, because they would. "just work" without having to put special effort in.
This sounds like the same sort of "We found out that the cost is not actually 0, and we want out. We can't say that though, so it's your fault"