Except this is engineering, not science.
Engineering is by inclination more conservative than science. That's because the failure of an engineering project is more catastrophic than the failure of a hypothesis, which after all is a result. But ultimately, after the engineer has done all he could to resolve competing priorities of cost, schedule, safety etc., it's whoever is bankrolling a project that decides to pull the trigger. The Apollo program was incredibly dangerous; more money and time might have mitigated that, but they were on a hard deadline to get to the moon by the end of the decade and were already spending an almost unthinkable fraction of the nation's GDP (0.8%) to do it. So they went ahead anyway. They lost three men on the ground and of the 33 they sent into space came within a whisker of killing five of them: all three on Apollo 13, and the LEM crew on Apollo 11 who almost ran out of fuel looking for a safe landing spot. And while you might point out that the Apollo 11 LEM crew still had 25 seconds of fuel left when they touched down, compare that to the margin of safety we set for aircraft, which can still glide if they lose engines.
While I agree broadly with the conclusion of the MIT critique, what I'm suggesting is that the engineering enterprise might have a degree of freedom they may not have considered, which is a willingness to take high levels of human casualties. The degree to which we value human life is a recent innovation. In the 1830s, trading ships began traveling between New England and California. That meant crossing Cape Horn in the winter, one way or another, and the casualty rates were appalling by modern standards. Sailors were routinely swept off the deck or fell from ice caked rigging to near instant death in freezing waters. But this was viewed as an acceptable price to pay in order to supply the New England shoe factories with cheaper leather.
While I don't think the proposed schedule is at all feasible, just from the time it will take to decide to *do* this thing, we might not necessarily have to wait until all the safety concerns are addressed to contemporary standards for things like ships and aircraft. Of course I wouldn't dream of boarding a ship to Mars unless I was 99% certain of surviving to death by old age, but some people might be happy to do it with 50%, or even less. Of course populating the mission with the wing suit contingent might have other unexpected effects...