NOT!!!
Frangmentation had nothing to do with any of the reasons given.
Android is open - And fragmented. Your telling me that if it wasn't fragmented, it wouldn't be open?
The market is massive - Because of fragmentation? I don't think so.
Diversity and flexibility - This is because of the wide range of phones and manufacturers, not because the platform is fragmented.
And both "Try before you buy" and "Device Freedom" can be had without fragmentation.
To me, fragmentation is the worst part of Android.