>The cost of animators and voice actors would be too much for indies to afford for a full season.
This is depressingly true and easy to see if you've ever followed any smaller, say doujin, anime project. Go to example would be Fantasy Kaleidoscope ~The Memories of Phantasm~. Making a doujin anime of Touhou was immensely difficult for the circles involved, so much so that there isn't any voice acting (which is why any release with a VO track sounds a little odd, the series was never officially voiced). It took over a decade to release 18 total episodes, each shorter than the TV standard 20-24 minutes. Episode 18 had to serve as a sudden and unplanned ending too after things stopped working out (though after a two year break an episode 19 has been finished and is soon to be sold).
That's on a far smaller scale mind. To keep up with an anime season to be properly recognized, you'd need a full cour of show to air weekly for 12-13 episodes. It's a daunting task for even the most organized of groups.
