Earlier quoted context omitted.
If these things really boost life expectancy that much, this sounds like a textbook case for eminent domain.
I'm no fan of the patent system, but "patent system promises spoils for coming up with great new drug, companies comes up with great new drug, companies gets spoils" is exactly how it's supposed to work. Yes, it's sucks that you have to pay, but that's how you incentives getting the wonder drugs invented in the first place. (I have my own take on this, but if anything this is a 'textbook case' in favour of the patent…
The drug companies are presumably pricing optimally for profit (but not for maximum public benefit, for which the optimum price is ~0). You could calculate the net present value of the drug companies' total profits attributable to the patent, add on 10% as a bonus, and pay them off. If the welfare gains of having cheap drugs are genuinely greater than the value of the patent to the holder, this would be win/win.