While I share your disdain of using limited web or advertising stats to determine actual device usage, especially from companies who are only seeking to sell their wares, Akamai is not the only study to say that phone usage is the same.
For example, take that recent Chitika study from December, which was widely quoted on fansites. From it, most people only saw headlines like "iOS Devices consume twice as much web traffic as Android!". Few ever took the time to actually read further down in the source material:
"While third-party and our own observations have pegged smartphone Web traffic share as a near-tie, Apple has a decided advantage in the tablet market, where its iPad is unquestionably the hottest seller in the sector. This advantage is the largest contributing factor to Apple’s lead over Android." - Chitika
The upshot seems to be that, at least in the USA, mobile web browsing is done two to three times as much on large screened tablets than on phones or e-readers, and there's a lot more large screened iPads in the USA than any other large screened tablet.
Edited by KDarling - 1/29/13 at 8:03am