The random fans care about the show and want to do the best job they can (although I’ve seen some pretty crappy old fansubs, with broken Engrish and/or outright missing lines, so the best the fans could do wasn’t always necessarily enough).

The corporations only care about how much profit they can make from the show and thus want to do the cheapest job they can while shoving it in front of as many eyeballs as possible. Most viewers accept it because it’s convenient and they don’t know just how bad the quality is because they have no basis for comparison. Those who do know how bad it is . . . complain on the Internet because they have no leverage to get anything fixed.