Stalls can be extremely difficult to recover from as it means the wings have lost lift, and therefore the control surfaces (which you need to regain stability)

Stalls can be extremely difficult to recover from as it means the wings have lost lift, and therefore the control surfaces (which you need to regain stability) have reduced or even complete loss of effect - a so-called 'deep stall'. As bad as MCAS is, it could theoretically (in practise, couldn't) be switched off in this scenario and the plane would be flyable. In the imagined scenario where the plane pitched up and began to stall, Beoing's logic is that without MCAS, the plane would be essentially doomed. Air France 447 crashed due to a (pilot-induced) deep stall; it was otherwise stable at cruising altitude. The root cause is without doubt relying on a single sensor, and then downplaying the importance of the system so that nobody opted for the additional expense of the extra sensor. Boeing also have to answer for their lack of transparency; their flight control logic has always left the pilot fully in control of the plane, and can override any automatic system. This sets them apart from Airbus, which under almost all circumstances will defer to the computer. In ways, the 737 MAX crashes are the antithesis of the 447 crash - the pilots thought they were in full command of the plane, whereas an automatic system designed to protect them malfunctioned, versus the pilots in the Air France plane believed the computer would protect them from exceeding the plane's capabilities, whereas the plane's computers could not get reliable data and passed full control to the pilots.