Android is a "commodity" OS, if you will. That is, anyone can build a device and put Android on it. Given that Android isn't complete shit and that people ARE building devices and using it, this trend is rather expected.
* Hardware. I.e. design, reliability, technical specifications * Commitment. E.g. providing firmware updates * Marketing. * Icing. By this I mean the vendor's "above and beyond" software offerings, such as a more polished UI, add on software packages, etc.
I have to admit that I find Android exciting as an economical experiment. I am not, however, an Android device user. For me Apple's relentless attention to detail has kept me captive (for now).