Less charitably: the FDA is intentionally slowing drug reviews as a bargaining tool.

It seems insane that drug approvals could be safely expedited by four months, at the suggested value to companies of $150-$300 MM, and this isn't done routinely. That revenue could easily pay for the extra eyeballs at FDA -- which are certainly much cheaper than the clinical trials themselves. I think if Congress were to question the FDA's workings, this could be prima facie evidence that the pace of drug reviews isn't set by hard constraints of public safety: it's slower than it could be, and agency leaders know it.