I'll give you an example (regardless of what has really happened with Facetime on iOS 6). My iMac G4 cost me £899 at the time. I got it in 2004. One year previous I bought a Windows XP laptop for about £399.
The XP laptop is still going strong with the latest software. iTunes 11, Firefox 28, Steam, Office 2013 all work fine (albeit some of it slow). XP has only just been ditched by Microsoft and will still probably have a few years left in it before Apps become incompatible. My iMac G4 however, has long since been ditched by Apple. OS X Tiger hasn't received an update in years (despite it being release long after XP) and I have to make do with older software versions (latest iTunes is version 9). It is no massive biggie, if you know what you're doing you can cope just fine(ish). But at the end of the day, it can't use iTunes Radio links anymore since they've been disabled in version 9, I can't sync it with OneDrive, I can't sync my iPhone 5 with it, I can't chat to friends on Steam, I have to use a recompiled and rather slow version of FireFox on it to be able to browse the web since Safari 2 is massively outdated... the list goes on. Realistically, my cheaper and older XP laptop is more useful today. All because of Apple's terrible software support lifecycle.