The problem that AAA studios face is that high-fidelity is their unique selling point, it's their niche of the market.

Every indie studio can produce a game that's fun, so you don't want to compete with those.
They have to produce titles with high-fidelity textures, with an extensive game world, story etc..

But as the indies get ever better, the AAA studios have to take more risks to be unique, which is why you see these ridiculous budgets and the invests not paying off so often...