I guess it is because we're buying their crap.
^One of the reasons I flat out REFUSE to support the bullshit companies shove down consumers' collective throats. Same thing goes for sell-out videogame companies like Nintendo who milk fans for nostalgia (aka milk their successes of the past) in order to get people to hand over their cash for sub-par gaming experiences!
It's a sad state we live in where fans will actually go out of their way to defend mediocrity and call detractors "entitled" or other nonsense in order to inhibit propagation of negative reception of a certain work, whether it be animation, videogames, etc.
If these companies know we will buy whatever crap they give us, there is plainly no reason for them to make any attempts to improve!