Well, not just Boeing but their competitors have heavy software involvement in the control system.*

In the case of the 737 family in particular, from its first inception in the 1960s it was to be a small commuter type carrier/ feeder. Its undercarriage permitted it to be lower to the ground than larger craft, to facilitate mobile stairways at smaller airports. That led to its engines being attached directly to its wings, unlike the podded mounting on most other Boeing jets where the engines are lower and the overall clearance of the aircraft requires it to be higher above ground level. As the airplane model evolved its capacity increased and it grew longer and its engines grew as well, both more powerful and especially more effient. More efficient subsonic jets led to a wider overall engine as the turbofans add width. I think this was occurring on the previous incarnation of the jet, the NG. But with the MAX Boeing was competing with a model of Airbus that was also more efficient. So they flattened the front of the engine mount for ground clearance but I believe they also pushed the engine forward of the wing to a greater amount than previously. This then changed the unloaded CG (Center of gravity). Both the engine performance and the engine location led to new airplane handling characteristics.

None of this is actually bad. These aircraft are long tubes loaded with people and cargo and their CGs are precisely determined for every flight.

The tricky bit was not that the 737 MAX was in any way less safe, but that now it did not behave just the same as the rest of the 737 family of Boeings and they wanted to make transition of pilots from older 737s to be simple and not involve a lot of extra training, simulator time and sign-offs with instructors. So the existing software was augmented by another piece of software, which was treated as, pardon the expression, 'seamless'. I'm not going to go any further into the weeds here, and I'm not in the business, just familiar with digital equipment and how it relates (or doesn't) to software. Another factor was that the software took data from angle-of-attack sensor mounted on the outside of the fuselage, and in this case it took readings from a single misreading instrument and Boeing charged extra for a backup instrument, so there was none.

This should never have happened. The main fault lies with Boeing design and corporate decisions with other potential modes of thought that the Boeing and FAA oversight and approval process was somewhat incestuous and again did not take a rigorous enough approach to the software development and integration. I think it is also true that a pilot who takes a bottom-up approach to understanding how his cockpit works might have been able to identify and pull the fuses to the control section of the instruments that was misbehaving. There had been an incident in one of the planes just the previous day.

Back in the days when I hung out in Starbucks a lot I got to talk to a pilot who flew Boeings (and was a big fan of the brand). He mentioned that he tended to know more than younger pilots about the stuff that matters when the error signals fly.

Long story short. Much as I am disappointed in Boeing and think they deserve a comeuppance, I personally would have no fear of flying in a 737 MAX.

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*There was a nasty Airbus A330 accident in 2009 where the automatic system apparently disengaged the autopilot due to ice on the pitot tubes and the crew did not catch what was really happening in time to regain control of the plane.