While that's certainly true, the differences between NT 4.0 and 98 weren't particularly huge. NT was certainly the better OS, and it's good that they decided to adopt it, but it wasn't really a paradigm shift, and Windows applications were still cross-compatible.

My intention isn't to say that Microsoft hasn't made significant positive changes over the years, but rather that Windows would be a vastly superior operating system if the same people responsible for it currently were able to start from scratch. Say what you will about Microsoft, they still have some incredible engineering talent.