That may be part of it. (Don't know.) But generally speaking I observe that both bank branches and mobile phone stores seem to occupy vast stretches of real estate that seem to be out of all proportion to what the businesses can rationally make effective use of. But I guess it's all part of projecting a bigger is better image.
The drug chains at least also functionally serve as convenience stores as well and, in my experience, they do get quite a bit of foot traffic. I actually find it a bit inconvenient when traveling internationally that this sort of store doesn't really exist--with the somewhat exception of the UK.