That being said, I will eventually die. Now, the question becomes what are the people that follow after me going to be using. I have kids in school: both use Chromebooks for school work, in one case a PS4 for gaming, and hand-me-down iPhones/iPhone SEs for social, gaming, and the like. Could they eventually need a PC? Possibly, depending on their career path/interests and the level of support for iPads, Chromebooks, etc. at the time. But they don't need it now. And I know people who are my age and older who limit themselves to iPhones/iPads for technology beyond the TV. None of these things are running Windows.
I'm a developer at work for internal applications (and some external). All of my non-server running things are web applications. They could be accessed by Chromebooks instead of the hp Windows 7 laptops we use now. I doubt we'd switch off PCs due to familiarity at the very least, but we don't need them.
https://www.statista.com/statistics/272595/global-shipments-...
The day of replacing a PC tower every 3 years are gone.
The sales of smartphones on the countries where pre-pay is the way to go are also declining.
My opinion on APIs have gone from new and bleeding edge to 'support it till the sun burns out'. Computers and meant to work. on linux or mac, no executable over 5 years old seems to work. But if download a .exe from the early 90's on a PC, it often just works.
In 100 years, the windows API and .exe are going to be the lingua franca of programs. there are many indications this is happening, valve baking WINE into steam, the fragmented package managers on linux, and no common runtime environment taking off.