Quite a few people only use their machines for emails, web browsing, watching online videos (usually of cats for some reason) or shopping with companies like Amazon.
For all intents and purposes, they could be running win2k or previous as long as they had a browser that could handle the online content and will never need the latest-and-greatest OS to be installed on their machines, not that they would notice or even if their machines could handle it.
I am currently working with one machine that has a 4Gig HDD and 256Meg memory that will never even fit the newer microsoft offerings, let alone be capable of running them.
Not going to happen no matter how much StevieJ wishes otherwise.
I discovered that browsers that handle modern content won’t run on Win2K. You need at least WinXP.
However, really ancient computers can still run the latest Linux, and all the current browsers.
I installed Ubuntu Server 14 on a 2002 computer with a Pentium 4 at 1.8 GHz and 1 gig on memory, and it runs fine. The desktops probably need something a little newer.