The golden age of PCs was DOS. Why? Because the OS made it very easy to write quick, powerful programs. DOS was a simple single-tasking operating system. It was easy to program on DOS because their were a lot of vendors with competing compilers that made writing applications relatively simple.
With the release of Windows, Microsoft made things much more complicated and then made it so complicated that Microsoft is now one of the ONLY company that can develop sophisticated applications on Windows. Unfortunately, Microsoft is not really very good at programming and does not need to innovate because they don't have any competition.