Windows sells more copies of its software the OEM route. Also, they sell specific versions that eventually end support. Today you might consider Windows almost a loss leader since Microsoft is diversified with many services on top of windows.
replyIt ignores the point. If I've bought BBEdit 13 for 60 USD three years ago and I'm still happy with it, I can keep using it for the rest of my life without paying more. If I want the new features, then I can pay 40 USD to get the latest version.
replyThis is a sane AND a sustainable model for companies, and actually creates MORE incentives for the developers to align with the user's interest: if the new update sucks and has features no one asked for, then nobody will pay for the new version and keep the old one.
There is no reason why previous versions of the software you paid a license for should effectively "disappear".