Two reasons I can think of, again specific to India. Desktops are typically connected to wired broadband which is way cheaper and also desktop users are usually better off than mobile only users. And only a fraction of new users are coming from desktop. Infact India is one of those countries where cinsumers leapfrogged desktops to go from no computer to smartphones.
Yea, I was more or less aware of all this, but I was thinking more of people like my grandparents/cousins in Delhi. I could understand them and people like them not using ad blockers for the same reason as people don't in the US (lack of awareness), but it's tough for me to do so when every person with a phone seems to be familiar with it (though this is belied by the explanation elsewhere on this thread that the popular browser in use has it built-in).
The bandwidth caps at my grandparents' Delhi house being super-draconian (they're about as upper-middle/upper-class as you'd expect). Though I guess their cap (a couple GB) is in this middle range where it seems low from the perspective of video streaming etc (and I don't even really watch TV) but is high enough that ads aren't really presenting much of a problem. This would be in contrast to the presumably much-tinier caps (and correspondingly higher incentive to block ads) that mobile users are presented with.
