The implication of the 'subsidy' argument is that there's a certain level of profit required to drive a certain amount of product development and innovation. In other words, to get the current level of drug discovery / development / etc., pharma requires the current level of return.
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.