Obviously rats aren't people, but a company obvious be edits when a molecule is discovered, synthesis optimized, and method of action/LD50 is paid for by the public before every cent of profits are privatized
Even if they don't market it, they own something tthat the public paid for
If the study/compound structure has been made public in some form, I think the public has gotten its fair share. The process that will take the compound from works-in-mice to works-in-people is quite difficult and risky. Pharma companies are very good at administering those things and (usually but unfortunately not always, hello Novartis) run those programs in a manner that ensures safety as much as possible down the line.
The Pharma company will spend its billion (roughly the cost per approved drug these days) and will recover many more times that if successful, but eventually the compound will become generic, and all of us will be able to get it for cheap.
I think there are many many problems with pharma, and I say this as someone who is trying to start a biotech. But the fundamental process above doesn't strike me as grossly out of line, it's playing to each players strengths. The reforms I would make would be around some of the pricing excesses, some of the patent/generics loophole abuses, and to find ways to address areas that are hard to make work financially in a private setting (antibiotics for example) through some sort of public/private partnership/prize system.