I suspect windows end-user don't care so much either, but the enterprise world does. The number of Fortune 500 companies that still use windows xp because they can't upgrade is most likely significant. People also often underestimate incompetency and things like "we lost the source of this software", "nobody knows how to upgrade this codebase at an affordable price".

This is the bread and butter of companies like RH (many companies are still on RHEL 5, and most of those have some legacy RHEL3 systems in my experience).