Unfortunately, your capitalist utopia isn't how the real world works, any more than the Marxist example you mention. Of course there should be financial incentives to go out and invent new things. The problem here though, is that a free market economy requires free choice, and choices made when under duress, are not free choices. All the leverage is on one side, and that is not free market. So I would say to you, how much financial incentive is the right amount? If we agree that it should be there, and we both do, then we must also agree that there is an amount, a level of incentive that gets such drugs made. If you want to stand by your example of 2001, and the drugs available then are OK, then by such an argument, so too should the levels of incentive of 2001 be acceptable. But times change, and the levels of profit have gone through any sort of ceiling or expectation.
It isn't always a case of just accepting drugs from 10 or 12 or 20 years ago. Sometimes, that new drug that we're very happy has been made, is the only drug that works. And then the choice isn't one of "well just go and use an older drug and suffer a little bit", it's a choice of life vs death (or crippling pain, etc). And this leads us back to the question of what is a free market? Because that isn't a free market any more than being forced out of your car at gunpoint by a criminal is a free market choice (that's an analogy, I'm not saying drug makers are criminals).
Us rich people (US citizens) aren't subsidizing development for the poor folk in Africa. We're subsidizing profits for those who own companies that develop drugs. So I circle back to the question, how much incentive is enough incentive to develop a new drug? Since we've already agreed as a country that we are going to promote drug development via patents and exclusivity, we've already accepted that we, (not the free market) control the answer to that question. While I wouldn't suggest that we eliminate patent protection and exclusivity, (why would I, I'm an entrepreneur?), but I am suggesting that we need to make changes.
Interesting reading:
http://www.fda.gov/Drugs/Development.../ucm079031.htm