I feel for these girls. When I saw Belladonna crying (or trying to stop herself from breaking down), I broke down as well (a little!!!!).
After the initial excitement of getting into the porn industry and doing things for the first time (ie: first gang-bang, first trio, first dp, first big paycheque, etc...), I'm sure most of these girls realise that they are simply objects and that their time is ticking,...and that once that time is over, they will just be pushed aside and left all alone.
Sex won't mean much to them anymore, they may have a hard time finding a real soul-mate, hard time having children, no emotional support, physical and life-long injuries to their genitals, etc....
Most of these girls are young when they get into this business. But as they mature, they will slowly realise that this industry is not a stepping stone, it is a tombstone in every sense of the word (as stated by Bill Marigold on that ABC special).
This can fukk with your mind in a big way