This is completely unsurprising, and this:

But let’s think about that 91% failure rate for a moment. When I bring this up in presentations, I invite the audience to consider what the auto industry would look like of 91% of new car designs proved unable to roll out of the factory, or if 91% of new airliner models were unable to leave the ground

Is an utterly irrelevant comparison. For physical thing we have engineering, and the practical application of the trades and craft, trial and error.

For modern medicine, we're only just starting to come out of the wild west era. Or perhaps slightly further along than that.

I'm actually surprised it isn't going up over time. That is naively what you would expect as the low-hanging fruit is plucked. So the fact that it's been stable is probably a sign that scientific advances are roughly keeping pace with the (presumably) increasing challenge of finding ever more targets for drugs.

As someone who works in research, this isn’t surprising at all. It’s hard to find something that treats (well most often reduces symptoms) of a particular disease. It’s even more difficult to find something that is also safe at the dose level it takes to treat said disease. Are there faster ways to do this? Probably not. AI is only going to help out so much, just like automated drug screening only helped so much since its introduction in the 90s.

Why does he conclude there is no alternative? He already argued this would be strange in other disciplines. So reform it.

There's an alternative that is slowly emerging. Many clinical trials "fail" but the drug candidate in question works really well for identifiable subsets of the participants. Right now pharma companies won't bother pursuing those drugs because they can't market it broadly. But it's still possible these drugs could help people in the future.