There's a lot of survivorship bias there. Case and point: the author did have this specific problem, and surely this problem is common.
Uber 'bought' their market - it might not even be viable when they run out of dumping money and have to raise prices.
I think there might be some opportunity in this guys startup with some pivoting.
Also I think there was some funniness on the feedback: Doctor used 'cost' as an excuse, but it may have simply been that the product was not hugely valuable.
Maybe for common drugs it won't help, but there are a zillion drugs out there, maybe doctors want a good reference.
The revenue model he didn't articulate comes from the drug companies. If Doctors used his tool, drug companies might pay for it in some way.
Finally, I have to say 200K lines of code sounds like a lot ...