App.net was born out of a visceral, snap reaction to Twitter's API decisions that, really, the mainstream didn't really care about. That's not enough to build a product on top of. What's more, while I sympathize with the developers who were negatively impacted by Twitter's decisions, one could argue the choices they made were _right_ for the product. If you believe that, App.net's decision, the inverse, was _wrong_ for the product (reducing quality and focus).

Or in short, most people just don't care.