It was a bad corporate ecosystem that caused the crash. The people at fault were the accountants that tweaked lines un Excel until they got the numbers they wanted amd then pressed reality into the service of those numbers. Bad software didn't eliminate pilot training on the new systems. Bad software didn't shortcut the required FAA safety certification on the system. Bad software didn't reduce the number of redundant sensors that fed the system.

Bad beancounters did all that. C-levels in suits who got million-dollar bonuses for killing 346 people to gain marginally increased quarterly results. Don't blame the software.