I think Windows is going to be reduced in price over the years to come, not dissolved. Microsoft realizes they've relied so heavily on Windows as their moneymaker, that they need something to replace that cash cow, given an unforeseeable situation.
I think when Windows 11 comes out, which I guess would be roughly around 2021 or 2022, Azure will probably be more profitable along with other Cloud type enterprising services. If Microsoft as a whole can put up profit margins company wide, as big as they are now, while selling Windows at $49 every few years, then more people will likely continue to be Windows users. Windows 11 at $49 might not make as much as Windows 9 at $199, but their Azure services will make up for that, while keeping the user base in tack.
Microsoft needs to figure out a way to get people to upgrade so they don't have to worry about legacy on multiple OS's. If they can essentially get everyone to upgrade at least once every 5 years, then legacy goes away and they can focus more on current models.
I really think Cloud is going to be more profittable in the years to come. Hopefully that means cheaper Windows and more focus on making those OS's better.