The difference here is that MCAS is an automatic feature that Boeing needed to mimic the existing 737 flight characteristics. They Created the need for the automatic system in the first place, then sell the safety redundancy as an option.
To extend (torture?) the automotive analogy, it would be as if the manufacturer substituted a new braking system that required preheating the rotors, installed software to automatically ride the brakes for the first 2 miles of driving in order to get that preheat done, then sold an optional safety feature to verify that the brakes were at the proper temperature.
The old way worked just fine without need for “emulation”. The new airframe required some software to mimic the old one, but they decided to charge you for the add-on to make sure that their band-aid worked reliably.
Again, yes, you may rear end someone, but this is not the correct analogy here. In this situation, the car rear ends someone while you are fully breaking because you didn't pay for the automatic breaking upgrade. This is a fail.
But here it was: pay to know if the automatic braking system will speed up the car for himself every time you first press the brake and then stop pressing it as you see that it's seems to be better:
Look at the charts above. Both pilots "fought" with the controls, correcting the plane course, then believing "it's corrected now" and then the plane sunk again and again.
