It's much more complicated than that. Sales in the US where they can charge more are what actually offer pharma companies good ROI. Effectively the US is subsidizing R&D for the rest of the world.
The question for me is how how inelastic this relationship is. The pharma companies would have you believe that if some kind of price controls of some kind were put in place, and the total amount of profit to be had was reduced, then the inexorable result would be a scaling down of the whole process: a sinking tide lowering all ships. Is that a realistic model? I don't know. Is there way to know? I don't know that either.
It's easy to make religious claims from either side, but it would be nice to have a better sense of the system dynamics here.
Those same comapnies then sell the same drug with pure profit (minus marketing & regulatory cost) in the US, for 4x the price because they have a monopily on it.