It's also an unsustainable business. How long do you think MS will be able to maintain backward full compatibility? 100 years? 200 years?

> Customers don't care why your software just broke or whose fault it was, all they care about is it broke.

Customers aren't engineers; they don't know better. We do. In any, it's going to be cheaper to abandon the stubborn customers than it will be to maintain decades worth of backward compatibility, at some point.