Repairing windows

Another day at the windows, as you can see we have the old style sash and case, they are great for being over 120 years old. They need some maintenance every decade or so and they will be good for another 120 years. They have a simple way of working which we can maintain ourselves. I think I am a big supporter of intermediate technology which I class these as along with our canal lock gates. simple but clever.
Why would you have modern windows that you cannot repair. My colleague has just had to replace his 10 yr old windows, what a waste of resources.