So's Canonical; but Ubuntu updates are free.
Yes, M$ makes a lot more money, but it does it by loading up-front fees on software (so by the time you need any service you've already paid for software with problems). They could, of course, use a model under which they charged for support instead,a dn used support feedback to improve the product. Oh, wait, they do that as well, don't they -or at least the charging bit.
If Old Windows is really the big problem, make an upgrade/licence for the latest version available at a low cost, and in the course of that legitimise any versions people are already running, Then you can pursue a proper security and upgrade model from then on.
M$ has to decide whether it's going to act as a responsible body which, due to its own practices, has effectvie control of a large proportion of a market in which there are serious security and compatability problems, or continue simply chasing the dollar until everyone gradually gives up on them. It's their call, and the market's eventual decision.