People are complaining about fragmentation on Android, heck people are even complaining about it on iPhones. How would you develop a good mobile OS with apps on hardware you can't test against? Even if the hardware problems was solved now, I do not think people would be happy to dev against the "platform".
People did just fine developing applications for PC with the huge variety of possible hardware, and for web where target hardware differs in size and power by multiple orders of magnitude.
