It's true that the alternatives may not be good, but if so it suggests that maybe publishing is a business that requires certain behavior.
I think the best thing that Doctorow could do is set up his own publishing business and show the big companies the right way to do it. If he's right, he'll get the best new talent and quickly succeed.
But I'm guessing he'll discover what the major companies know: the consumer is fickle, developing a new book/movie/song is expensive, and only a few hits pay for the rest.
There are plenty of fine, even higher quality and credibility, publishers out there.
In fact even a mediocre university press likely has higher standards, in just about every conceivable quality aspect, than even the best imprints of the big 5.
