It is possible they see their OS as being suited for one-handed devices. One of the things I do not like about Ice Cream Sandwich on my Galaxy Nexus is Google has removed the "+"/"-" buttons in most of their native apps so now I have to either use some really unwieldy one-handed finger contortions or use two hands to zoom in and out. I think an argument can be made that in many instances at least on a smart phone as opposed to a tablet multi-touch while being fun to use is actually a step backwards in usability.