The interesting thing is the difference between "shipped" and "sold". For instance, you posted:
In 4Q11:
ASUS sold 600 thousand not first generation devices running Android.
In 4Q12:
ASUS shipped 3.1 million units in a solid 4th place (that may be counting Nexus 7 devices which were a hit).
I assume "shipped" means released into the retail network and "sold" means actual units transacted for cash.
This is something that I see with the Surface sales too. With specific reference to the Surface RT, MS says that they "shipped" 1.1 million units. But how many of that 1.1 million units were "sold"? And, there is where I think the critics are having a problem.
Regardless, I think after MS releases "Blue" for RT, things will look up because it will wrinkle out the not-so-good elements in RT at the moment. Or, at least I hope so. Why? Because, I think the Surface RT is a very good machine. I also think that MS totally screwed up its advertisement, launch and distribution. By mid this year (or whenever it is that Blue comes online), MS should have got its act together. I don't foresee Apple doing anything earth-shattering with the iPad at least for the next 12-18 months. Any improvements will, at best, be incremental. But for the Surface RT (and for Win 8 more generally) any improvement will be a dramatic leap in capability.