The internal frameworks developed in .NET shops are inefficient and mediocre not because the Ruby or Python communities are full of pure genius, but because they have more than a single person continuously working on improving them. Pythonists and Rubyists have a culture of sharing and coding in a constant loop of feedback. They talk to and work with each other. People in .NET culture do not. As a .NET developer I have rewritten code that has been created several times before, and it will die in obscurity behind the closed doors of the companies I've worked for.
This is something I only begun to realize by talking to JS, Ruby, and Python developers. I've been teaching myself Ruby since September and hope to leave .NET as soon as I can.