The idea of selling safety systems (indicators that the angle of attack sensors were in disagreement and that the MCAS was engaged) as expensive options was pretty short-sighted and seems greedy on the part of Boeing:
They didn’t buy the DLC: feature that could’ve prevented 737 crashes was sold as an option

From what I recall, the simulators also weren't accurate as to what a pilot could experience with the 737 MAX. This was intentional as the 737 operators and Boeing didn't want to require significant retraining with the new platform.

The entire episode indicated short-comings in manufacturing, FAA oversight, and pilot training and experience.