Well, it's not like you couldn't make money by inventing an ideal cure, you just can't do so sustainably, but for better or worse sustainability has never been a particularly high priority for businesses.
I think patents make any kind of free market approach difficult if not impossible, but it's not as if there's no monetary incentive to invent the 'best' cure.
I think there's a lot of survivorship bias in play here. Whatever company that makes the most money will grow the most relative to others.
The big companies will always be the most greedy one's but most companies may still have slightly different priorities. Companies that survive must be long term economically sustainable. Consequentially most companies that exist will likely prioritize economic sustainability because those are the one's that survive.
However, it might still be that it makes sense to start and work with temporary companies that are not long term sustainable if they do fix a problem?
I think patents make any kind of free market approach difficult if not impossible, but it's not as if there's no monetary incentive to invent the 'best' cure.