I think that that demand is more elastic than most give it credit for being. There are often many ways to treat an issue, with different costs and efficacy, and the demand for which and how many depends on who's footing the bill.

Similarly, I think most people vastly overestimate how much of Healthcare expenses involves an ambulance ride or emergency room

The trump administration did an executive order that forces hospitals to list all their prices. Imo easily his best move. Now, the current implementation does not work for a myriad of reasons that are mostly "hospitals have good lawyers and don't want to reveal prices" but the law can be fixed. A working implementation would make price shopping easy as someone would build a centralized site and you could have your health care provider put in the treatment needed along with your location and distance willing to travel.