Why does Android 3.x have no market share?
Honeycomb was a tablet-only version of the OS
It was only ever released for a few devices
The source code was never released not released until the source for Ice Cream Sandwich was available, and even then the Android devs noted that 3.x source was not complete
It never had much in the way of market share


See also:


What percentage of devices have each of the Android versions?
Is Android 3.0 Honeycomb only for tablets?