[oneplane]

Multiple reasons (as outlined partially by others):

  - It is incredibly hard to make something so versatile work well everywhere, all the time, for everything
  - It is even harder to get multiple stakeholders to do this consistently
  - And it harder still to do this if the business case doesn't allow for (long-term) support

This is mostly a business problem and not really a technical problem. Wi-Fi is similarly pretty badly implemented, for similar reasons, but the upside is that it doesn't have a billion specialised profiles, it generally just has to pretend it's encapsulating network frames the same way ethernet does. As long as it can do that, people can make use of it.