I could be wrong but I suspect that many publishers have internalized consumers' desire for more visually attractive games as a need to produce games with more technically advanced and more realistic visuals. Now, in spite of what some supposed "Game Developers" on this site might claim, there is a massive increase in the work needed to create games using these technically advanced visuals.
The unfortunate thing for most developers is that consumers see more value in lower-tech highly polished graphics than higher-tech poorly crafted visuals, and (when the graphics are at a similar level of polish) consumers do not "reward" more technically advanced visuals at a level where it justifies the money put towards them.
This isn't saying that pushing the limits of realtime graphics has no value, but (as a publisher) you have to know when it is appropriate to let a game's budget balloon to $40+ Million and when it makes more sense to keep the visuals simpler and the budget at a more modest level.
