I think its fair to say that a lot of people buy a cheap Android tablet because theyre weirdly expecting it to work like far more expensive devices, and then when it doesnt live up to expectations go back to browsing the web on their phone, computer, or whatever else they were using before they had the tablet. Sure there are people out there buying $100 dollar tablets as their only connection to the web, but I would submit that most people would opt for a $100 dollar netbook instead, generating numbers that are not reflected in these statistics.
Basically all Im saying is that the UX of the Nexus tablets is hardly representative of the Android tablet ecosystem as a whole. By and large, Android tablets fall far short of that standard.