Edit: Actually, they've just changed their "startup" pricing and it isn't publicly available anymore. It might actually be better, if they allow you to have more than 3 devs.
Define "independent developers". Because a lot of them do use Xamarin.
A lot of people are vocal about the price, use it or not; you can't pretend it's not true.
However, I do think their asking price for the edition that lets you use Visual Studio is a bit steep (I also pay for it, but still think it's kind of high).
As the copyright holder RoboVM (or Xamarin) can chose at any time to close source the code and change the license for new versions.
(CIL BYTECODE / JVM BYTECODE) => LLVM => NATIVE
Up until now RoboVM has been featured frequently by Oracle in an attempt to mask their weakness in the mobile space (since Oracle doesn't acknowledge Android). I wonder how quickly this will stop.