In my home all the machines are 20+ years old and work perfectly fine (oven, washing machines, vacuum cleaners, irons...) not to mention things that don't need electricity, which are 30 or sometimes more than 80 years old (furniture but also cookware, etc.)
A bike that's 20 years old feels ok and modern; a bike starts to really look ancient at maybe 50 years old? We can still drive cars made in the 80s and 90s (and they're often better than newer ones).
Windows 7 works fine, why should it go to waste, and the machine it run on, and why should people be forced to upgrade and change or abandon all the little customisations they have set up that makes their lives easier? Don't we have better things to do with our time than relearn a new way to do the exact same thing?
I understand the motivation of vendors to try and sell new things; what I don't get is why we put up with it.