Pilot Mike and Fly Aiprt, you're rather missing the point. MCAS (and countless other systems) are less than 100% robust because it's assumed that if they do something stupid, the carbon based life forms sitting in row zero will take over and fly the aircraft. However, it's been repeatedly demonstrated that at least some of those carbon based life forms - otherwise known as pilots - are not completely up to the task (forget MCAS, think AF 447). If the designers have to design all the systems on the aircraft assuming the pilots won't take over and do the right thing when something fails, then why have pilots?
Of course this would take a complete re-think of how aircraft and automatics/avionics are designed, with many levels of redundancy and backups. The 'we must have pilots' side keeps pointing to cases where the pilots stepped in and saved the day when the automatics went south - but that's how the system is designed, assuming that when things go wrong the pilots will step in and save the day. The designers would not design the automatics that way if they couldn't count on the pilots to step in.
Now, I'm not suggesting we're to the point where we can design the aircraft so we don't need pilots - that's still decades away. But when pilots become completely overwhelmed and demonstrate the inability to even remember to pull the throttles back so they don't overspeed when something goes wrong, it moves us one more step in that direction.