"Twitter is a B2C product, so they're going to limit B2C"
  
  "Now, Twitter is not a B2B company"

Awesome. Now they aren't, and when they decide they are? And speaking of acquisitions - well, they can essentially kill you willy nilly so you better settle for the price they want.

The dangers of sharecropping are well known around these parts, Twitter has squandered their reputation and has brought these things to the forefront of anybody who would consider building a business on top of their platform. It will not end well for them.