Then, people started developing things like DXVK, and then Valve threw their weight into it.
DXVK is a game-changer, no pun intended. I've used it and seen Windows-like framerates where WINE alone would have them at half of that. I never liked Steam much in the past, given that among other things, it's a platform for DRM, but no other entity has done more for Linux gaming than Steam has, and now with their new commitments to the Linux platform, I am cheering them. Gabe Newell's comments about what MS is trying to do with Win 10 and the MS Store are spot on, and making a platform that no one company can ever control into a viable alternative to Windows is the best way to ensure that MS never accomplishes its goal of a captive, iOS-like walled garden for Windows.
Steam, though, is only a gaming platform, so even though the same principles apply across the software spectrum (MS can't close up the walled garden if there is an alternative it can't exterminate), someone else will have to step up for non-games.
Given that MS Office is the 800 pound gorilla of business applications, and that the company that develops it is the very same one trying to set up this walled garden, that seems unlikely, at least in the short term. If MS is truly serious about becoming a cloud company, which I think they are, they really should not have a problem offering a Linux version of Office that is on par with their Windows offerings. After all, Linux users can be customers of cloud services too, right? If it's all about the cloud, what difference does it make how one gets there? Linux users are not users of a competing platform-- they're potential cloud and application software customers.
If that ever happened, it would be down the road a bit. Right now there's monetization to inflicted upon the Windows-using community, and MS very much wants all of those recalcitrant Windows 7 users to move to 10 to be monetized for a few years before they get fed up enough to overcome the barriers to leaving the Windows prison. Once the Windows-using community has been monetized and abused to the breaking point, only then can MS start being serious about Linux applications.
I don't know that MS will ever do that, but it seems clear to me that they love the cloud and want Windows dead, but only after squeezing Windows users for all they can. Nothing else makes sense... it's not plausible that MS really thinks they can treat Windows customers like this and keep them long-term. Vendor lock-in will keep them in the line of fire for a while, but that won't last forever.
It naturally follows that MS would offer a version of Office for whatever platform(s) take over after they leave the OS market.