Is 20 years actually that long for a drug? Drugs tend to have 12-15 years of actual patented time in market given the time eaten up the approval process. It's not like software where that time lag might make the patented drug obsolete by the time it becomes generic.
What "insurance laws" "subsidize" drug costs?
The cost of regulatory approval is high, but that's justified because the economic cost of a bad or even just ineffective drug piles up very quickly. Reduce the life expectancy of 1,000 people by 10 years (or give them an ineffective alternative to a drug that could extend their life by 10 years) and that's a billion dollars of damages right there. Is there a cheaper solution than extensive clinical trials that accomplished the same result?
It's not clear there is. Remember, what really makes approval so expensive is that most candidate drugs don't get approval. So the investment into all the drugs that don't work has to be recouped from the ones that do. But the fact that so many drugs fail at the clinic trial stage suggests we don't have better ways of predicting whether drugs will be safe and effective. Drug companies don't invest into drugs that don't pass approval for funsies. If they could determine a drug wasn't going to pass approval before the clinical trials, they'd do it. It'd be pure profit for them. Also, the fact that so many drugs don't pass approval suggests that the FDA is keeping a bunch of ineffective and harmful drugs off the market. The cost of getting rid of the FDA has to account for the cost of those bad and ineffective drugs.
Also, getting rid of these things would not make the drug industry a "free market." In any advanced society, the government will pay for drugs for elderly and poor people. That creates an entity that can exercise monopsony power. Get rid of patents on drugs, then you get the free rider effect undermining R&D. And get rid of the FDA, and you end up with a market with huge information asymmetries that allow drug manufacturers to sell products that don't work without customers having a way to know that. These would destroy any hope of a functioning competitive market. You can't talk about markets while pretending only the parts of economics that comport with your world view exist.