Drug companies also fund their own research, to the tune of massive expenditures. What you’re suggesting would incentive these companies to disengage from partnerships involving public funding. Whoever pays for the research, each company’s goal is to profitably sell a non-generic treatment. If the only way they can do that is to eschew public funds, they will do this and the result will be less cooperation and a far reduced ability for the government to influence the direction of private sector research, and more importantly shape private sector manufacturing and the quantities of specific treatments supplied to the market.