I think you are on to something. If you are "savy" internet user, you probably hang a bit longer on the desktop than the average population because you are also a power user. If you are a "casual" internet user, mainly checking some social site status, etc, using a mobile is enough. Or to say otherwise, prosumer vs consumer. And it is more likely that you will use an adblocker if you belong to the first part of the population.