Based on the very large revenue from foreign patients who come to America to get cancer treatment on their own dime, those patients and their families care about getting the best treatment.
OTOH (or the other other hand), I'll bet that you could make a strong argument for stopping new drug development entirely. Simply sell existing drugs for as little as possible. It wouldn't surprise me if most of that research has insanely high marginal cost with little benefit at this point.
I'll bet you'd have a healthier public, on average, if this happened.
Under this rubric, "cheap" lifesaving drugs are viewed as an arbitrage opportunity. If a lifesaving cancer drug costs $20k per month, then why should a comparable MS treatment be "given away" at $15 per pill?
Also a huge percentage of new drug research is not geared toward creating new and interesting treatments: it's based on making small changes to existing molecules to preserve efficacy while making something "new" enough to be patentable.
It's really not that simple, even if some political talking heads would like you to think so. People travel to the US for some treatments, and people travel from the US for others. It's not even clear if there is a net inflow or net outflow.
All this really shows you is that people with the resources to do so are willing to travel for care, which shouldn't surprise anyone. Either for "the best treatment" (which depending on disease and treatment could be many places in Europe, US, Canada, etc.) or for more affordable treatment (cf US residents traveling to Canada for drug renewals).