This is a really negative take. They could also add hostile terms of service at other times or do hostile things. It's about cost and marketing.
Windows N+1 will share a majority of code with Windows N. Microsoft would now have to maintain two copies of the code N and N+1. This is added cost.
Alternatively Windows could do continuous releases, but this is less fun to market, and users might not like big changes happening many times a year instead of all at once, etc. There are also compatibility challenges for this since behaviors are tagged to such specific versions.
It's amazing how nobody complains about this with any other operating system -- at least since Leopard/Snow Leopard (IIRC - that was the one that had major compatibility EOL).
The problem isn't the EOL. The problem is that the newer versions of Windows are user-hostile and the alternatives are being retired.
