forced backwards compatibility

I certainly agree with most of the badness of the things that you cite except for the above. I think you have the direction wrong when you think of which way the force was for backward compatibility. It was not from MS to customers. It was the other way around.

MS had no choice but to support backward compatibility. Their desire to survive forced them into this position. Had they chosen to abandon it, their customers would have left them. It was customer demand for compatibility that kept it around.