The Dreaded New York Times has the article Doomed Boeing Jets Lacked 2 Safety Features That Company Sold Only as Extras.
Boeing’s optional safety features, in part, could have helped the pilots detect any erroneous readings. One of the optional upgrades, the angle of attack indicator, displays the readings of the two sensors. The other, called a disagree light, is activated if those sensors are at odds with one another.
The Dreaded NYT has answered one of the first questions that came to my mind about the crashes. I wondered why the engineers who designed the plane never thought that the MCAS system should warn the pilots when it decided to intervene and countermand the pilot’s inputs through their handling of the cockpit controls.
So the designers could and did foresee what could actually go wrong, but management decided that they could squeeze more profit by making these safety features optional if you paid extra for them.