The problem is that regulation is so expensive there isn't any financial motivation in researching does that are unlikely to generate massive revenue.
The reason for this is FDA is fundamentally extremely conservative. The people that run the regulatory system are just faceless bureaucrats and are risk adverse. Their pay is based on seniority and there isn't any financial motivation for them to take risks or stand out. FDA is nothing more then a collection of individuals so the motivation of the agency is a mirror image of the motivations of the people running it.
To put it bluntly:
When diseases like cancer or influenza or kill people the diseases get blamed. But if a drug makes to it market and ends up maiming people or killing them then the FDA gets blamed.
So from the FDA's perspective it's much more important that we have ultra-safe drugs then it is to have new drugs to cure and treat diseases.
The regulators are going to take the default position that more testing and screening and expenses are good. While allowing consumers and doctors to take risks to treat diseases is bad. And over the decades it has just gotten more and more and more and more expensive to get the drugs out to the public.
And since it's too expensive to make new drug companies because of the regulators then you will never see any smaller nimble companies come in and compete with them and force the big companies to behave themselves.
This is why you see all the generic drugs being bought up in the past couple decades. During the Obama administration they signed regulatory changes that rose the cost of validating generic drugs considerably. It wasn't so expensive that it would drive generics from the market, but it's expensive enough that you can't make new generic drug companies. So the big name brand drug companies just buys them all up. And because of that they no longer face competition from generics. They own both the name brands and the generics.
If it was cheaper to make generic drug companies this approach wouldn't work. People would make new companies for the sole purpose of getting bought. It would make buying companies up to kill competition unsustainable.
I've worked in heavily regulated industries before and it's a pretty obvious pattern. Regulators regulate. Costs go up. Competition goes down. And then the big companies become isolated from competition because it's just too expensive to compete with them. Then the government has to bend over backwards to ensure the profitability of these dominate corporations because if they were to go out of business there would never be any replacements.
It's a form of market lock-in. Over regulation effectively becomes a license for these big pharma companies to do pretty much whatever the fuck they want. They love it.