In general, anime adaptations are just ads. Their primary purpose is to advertise original novels, manga or games. More often than not, anime studios have a very limited budget, only 12 episodes to work with and the slavery committee (aka production committee) controlling their every move. As such, anime studios are just contractors bound by their limited resources and obligations. There's very little chance of anime adaptions being profitable, so all they need is to make a good enough product and move onto the next project.

Exceptions can happen though (Re:Zero, Tensura, Monogatari, Katanagatari), but only when studios have resources required for making a quality adaptation in the first place.