I use Ubuntu as my primary desktop OS and it works well -- and I can say that it does in part because when I get an occasional itch to play a game, wine works for me more often than not (most recently: Hearthstone).
If I still used Windows as my primary desktop OS, I wouldn't care about wine either, but then again I wouldn't be the target market, now would I?
You are right, I am not the target audience. The point is that the effort required to keep a project like Wine going could be better spent on doing other things that make the overall Linux experience much more appealing.
I used Ubuntu as my primary Desktop during the stone age of Vista and even then, using Wine was a painful experience compared to just switching to Windows.
VM or full Install, you need a license to do that. Not everyone is ready to pay just to use some incompatible tools.
I agree on the effort part though : it's a lot of time loss on something less and less useful nowadays.
At this stage working on something like wine seems like a misguided effort. I use windows as my primary desktop OS and it works well. For non-windows users, a vm solution would be way better than a kluge like wine.