10 years of support is standard on Windows, and they might be longer depending on the situation (see: Windows XP) or if you're enterprise and pay up (see: Windows 7).
And then there's what you allude to: A stable Windows environment that will, in most cases, run ancient code mostly fine assuming they were written to specs of the time or it's a very important piece of code (eg: Simcity).
And then there's what you allude to: A stable Windows environment that will, in most cases, run ancient code mostly fine assuming they were written to specs of the time or it's a very important piece of code (eg: Simcity).