I think an interesting solution to consider is a sort of drug bounty program run by the government. Right now, companies put up their own capital to fund drugs, and get a big payout (via patent exclusivity) if they succeed. This is a bit problematic, because regardless of the expense of the cost to develop the drug, it is in the interest of the drug companies to charge as much as possible for the longest amount of time to maximize return on investment (personally why I think there are so many long-term treatments for diseases like HIV rather than full-on vaccines). But if the government were to say “we will give $X billion to the corporation that provides a drug that meets Y conditions, with the caveat that that drug will then be sold for $Z per course of treatment or immediately go generic”, then public health policy could direct certain aspects of drug discovery, and lead to more affordable outcomes. There are still issues with this sort of plan, but I think it has the potential to be workable.

That’s expropriation. If you have a rough idea of the target market, growth rate and you know how much longer the patent will last you can upper bound and lower bound the loss of the intellectual property holder.

If you want patent free medicine I suggest at least looking at what medical research looks like without the possibility of supernormal profits on some drugs to make up for the losses on all the many, many other drugs that don’t make it. One plausible model would be how the Soviet Union did drug development but I know very little about that bar that the pschopharmacologicals in Russia etc. are in some respects quite different from those used in the West.

This would certainly prevent new expensive drugs from entering the market. Unfortunately, it won’t result in new cheap drugs entering the market (something that the current system provides, despite all its problems, after a few years).