Actually, the last Windows OS that was probably justified by new features was Windows 95
No, you're getting confused by the two sides of the same coin. One side is the meaningless changes that create user confusion and lost productivity. The other side is the lack of meaningful changes that would justify the upgrade.
Sorry, but I don't count "We're pointing a gun at your head" as constructive justification.
Microsoft's monopoly has become quite destructive to the entire industry. No significant change is permitted without Microsoft's blessing. Meanwhile, their monopolistic position has destroyed their competitive edge and made the company lazy. There really are lots of new things that could be added at the OS level, but that would be hard work.
Considering problems without solutions is pointless, so here's the solution. Cut Microsoft into three to five pieces. Each new company starts with a complete copy of the source code and an equal share of the employees. I suppose they should use a draft system to make it as fairly competitive as possible. Then the new teams compete. One of the daughter companies may focus on security, while another pushes the OS towards higher performance and a third focuses on compatibility--and the market gets to decide which is best. The new competitors can even share as much information as they want (especially for standardization), as long as they share it with the rest of the market.
The shareholders would NOT suffer because the most important result would be faster overall growth. Even if one child company does poorly, that would be offset by others that flourished. Of course, a shareholder could hurt himself by selling off or buying the wrong shares, but that's always true. Or maybe that's only the second most important result? More freedom from meaningful and unconstrained choice is important, too.
Sadly, this model of non-cancerous growth won't happen. American law requires each large company to grow like a cancer just to survive. That's what happens when the rules of the game are written by the most cheaply bribed politicians working for the least ethical and greediest businessmen. (The 99% of nice businesspeople just don't matter anymore.)