The release of new versions at regular intervals is probably reasonable to keep up with new useful things that can be done with new hardware and with new software ideas.

Microsoft has generally maintained "support" for each version for at least ten years, and nothing prevents anyone from continuing to use stuff well beyond that as long as they can keep compatible hardware running. The hardware does "wear out" and replacement about every ten years is fairly common. Based on advertised MTBF (Mean Time Between Failures) it can be predicted fairly reliably that for computers run 24/7 for ten years, at least 30% will have had at least one hard drive failure (if they're running one HD). Other things like the integral graphics chips appear to have had somewhat shorter average useful life but reliable reports are pretty sparse.

New OS versions intend to take advantage of new kinds of hardware, but the more important changes probably have been changes in "security." It's an unfortunate consequence that changing how the OS manages the programs frequently makes it very difficult to allow continued safe use of a program that uses an old feature that malware distributors have learned to manipulate.

While the "security patches" still keep coming, it might be worth noting that the vast majority of successful malware attacks now get in through the nut in front of the monitor, because even Windows has made it the only really easy hole left for those who want to attack individual users, and it can't be patched as long as the user is the only one who can do anything about it.

IFF you can use an old enough setup, you might actually see a degree of "immunity" even if your stuff is full of holes. Malware distributors who want to take over your machine to do something with it don't particularly want anything "old and slow," and the others may assume "Nobody using junk like that has anything worth stealing."

(Some statistics support the last remarks, but I won't try to present proofs. - Don't ask.)

[Maybe more later, after I take care of business.]

John