The question I was trying to answer was whether there's anything wrong with being prolific. To me the number of these books sold tells me more about the audience than anything else. There's certainly nothing wrong with doing what they're doing though and, judging by the video, they'd be the last ones to pretend they're producing anything other than pulp fiction. By all means, good luck to them, but it doesn't mean I have to like the stuff.
You did ask a specific question and it seems a little unfair to criticise when people give you an answer.
Mike
PS I'm well past my college years but I do remember them fondly