That would be a legitimate observation, except in the case of educational purchasing where the decisions to buy iPads in bulk is being driven by a bunch of things other than legitimate educational use.
Our Moodle site is used almost exclusively for so-called hybrid instruction, meaning that a lot of the interactive content is being consumed by students using school-based hardware. We have more than one school recently investing in iPads, only to find that they didn't interact with existing content management (including Moodle) as they expected. That's a huge mistake, and one which could have been avoided by listening to some of the observations made here.
iPad advocates use the popularity argument when promoting their own interests, but avoid it when looking at content and resources which are not handled well by iPads. That's why, as an educator, I prefer to talk about pedagogy rather than hardware. Hardware SHOULD be the caboose on that train. All other things being equal, it should not force us to choose one instructional practice over another.