That’s not how it worked. They were indeed awesome at backwards compatibility, but the proposition was NOT some principled mindset about long term ownership. It was that upgrading wouldn’t break what you have, overcoming a major sales objection. I think the proposition is better understood as one about FORWARDS compatibility — Windows was (and is) a brittle, poorly architected mess, and so the idea that anything built on it would stay working as the platform evolved was clearly insane and developers would never be able to keep up, so Microsoft absorbed much of the cost. This was actually something they did quite well — a good analogy here might be the heroic response the USSR had to the Chernobyl catastrophe, in which they skillfully managed a disaster whose scope was possible only through a long tradition of poor decisions — and this deserves recognition.

But the reason I think it’s better to think of it as forwards compatibility is that Microsoft gleefully used file formats as a means of driving the upgrade treadmill. Yes, the upgrade to Office 97 would keep everything working to approximately the same level of reliability you had already resigned yourself to — but by default, the files it kicked out would be unreadable in Office 95. There was Save As and an optional free converter… which tired 90s office workers didn’t know about, or particularly want to think about. In the age of literal floppy disks, the friction this created was a significant motivator for businesses to say “fuck it, fine.” Microsoft’s true genius has always been in knowing that “fuck it, fine” is the only bar they ever had to clear, and that through the power of lock-in and sheer institutional inertia, they can drive that bar deep into the belly of the Earth.

Thus, Azure.