Microsoft is a business and a new operating system means bigger profits. Windows 7 isn't bad, way better than Vista. Most complaints are because users are unfamiliar with the operating system not flaws in it.
They don't support Windows 98 anymore either. Doesn't mean they don't work just no security updates. I was running XP at work and my company got me a new computer because with all the hackers out there a Windows XP system on the server was a backdoor to some serious trouble. Not worth the risk and now I have to fight with Windows 8.