It could be ...
Outside of steam which (I believe) has a very dedicated userbase, most people seem unwilling to pay much (or anything) for games through digital distribution. A small, very inexpensive game with lots of low cost add ons could easily earn far more than a more substantial game that is sold at a higher price.
While I don't want to see this business model form, I think the only way the mainstream will (really) accept larger games through digital distribution today is through a modified shareware model; essentially, where you have multiple "episodes" and gameplay modes that are sold below what people are willing to pay.







