They could've just shipped YEdit, which is open source: http://www.malsmith.net/edit/ but there is NIH syndrome in MS.
Yedit actually was written by a Microsoft employee :P
It had some problems however with handling unicode (iirc). Basically, shipping yedit would have required a huge re-write of its underlying text buffer. In the end the discussions we had with Malcom concluded that just writing a new one was probably easier and more maintainable in the long run.
At first I tried really hard to use these tools, since my work laptop runs Windows, but gradually I accepted that no, even the experienced users aren't doing any better, these tools are just worse than the ones I was used to, and so I use a Unix shell and terminals designed to run those shells instead.
There were Windows/ Microsoft tools where I found things to like. C# is at least arguably a better Java for example. But a lot of the things I expected to find had benefits were just disappointing.