Wouldn't it be plausible to say that the costs of effectively protecting performers would be high enough to basically screw the reason that most of them get in (quick, easy money)?

From what I can tell, porn pays well (hourly) because it's dangerous, not because of the infamy or any other side-effect of appearing in adult films. Now, let's say that there's a doctor on the set, that county/state health codes are enforced (in terms of # of toilets, sanitary conditions including unbreakable lights and a lot of other stuff that most non-employers take for granted, as well as the obvious stuff), and that a satisfactory liability insurance is in place aside from whatever people already have.

This is going to eat at everyone's bottom line, but the people who can least afford it are the performers themselves. Are we now talking about serious pre-screening of new talent, which would probably be required by insurance companies? That would make it a bit less attractive for girls seeking to pay the rent/boyfriend's drugs/gambling debts, if they can't turn it around in the two or three days it takes for an HIV test. The other costs would, let's say, slash everyone's income by about 50% (and I suspect that a significantly higher burden would fall on the performers, not the producers). Is porn still an option for new talent?

So I can see what you mean, but there's a cause and effect outside of Holly's mom opening her wallet and doing the right thing. One company alone couldn't do it: they'd be out of business. An industry-wide change in regulations would effectively make porn safer, but the high-risk job gets the high-paying check.