I don't mean to disagree with you in spirit, but profitability is pretty closely entwined with probability. So companies are chasing solving problems that more people have, even if it's for the wrong reason.

A metric other than profitability seems like a terrible target for private research which (outside of a charity or cause-driven org) needs to justify its expenses.

In the US alone, we have dozens of grants, programs, and funding sources for things like orphan/rare diseases.

The reason why it's less profitable is because it will help less people. If profitability didn't dictate what is researched, widespread diseases would get less researched and rare diseases - more researched, which would be a net negative.

IMO the issue isn't discovery and research, it's development. Unless companies foresee a good return for buying/licensing/etc rights to treatments, discovered drugs with potential just sit there.

What sucks is when drugs are deliberately not brought to market, but kept in portfolios, because it might impact sales of other existing cashcows. For example, Gilead has a history of staggering the release of new drugs only once their patents expire for similar drugs they already have on the market.

I find it makes more sense if you drop the corporate analysis and just think about people.

Money motivates them and is why they go into hospitals or research labs instead of staying home with their family or friends.