Big pharma excels at the subsequent stage: taking the best ideas generated by scientists and bringing them to market, using its huge financial firepower to navigate the complex regulatory environment.
If the government were to nationalize the industry, wouldn't the regulatory environment become simpler? Regulations exist because of the fundamental antagonism between profit-making and safety & efficacy. If the sector were nationalized, that would shift (and possibly diminish) that conflict.
Industry may well have expertise in the expensive process of ensuring safety and efficacy, but if that's made more expensive by having regulations thrust on it from outside, why not save the cost?