At least this software problem wasn't actually flying the 747. The IBM RS6000 was a new beast in 1990, how many people at the time knew that the C compiler would do that with those flags set? Obviously this is situation where 100% comparison test with the previous paper book seems justified.
Boeing gambled the companies entire future on the 747 being a success, it was built by a company that wanted to build the best machine possible and everyone involved knew that the effort put into the designs & actual metal bashing could be a deciding factor in the life or death of several hundred people. More to the point, Beancounters were not involved in the design decisions.
Half a century later Boeing gambles the companies future on a software cludge to shortcircuit the type certification process and produce a cheaper aircraft to buy.
The 737Max will forever have a bad smell associated with it because the decision was made to save money, far worse that the Comet-1 design problems due to the unknown effects of how metal fatigue happens, far worse than the DC-10 where shoddy maintenance brought them down. The only good things to come out of the Max will be that software will now be rated level with design & maintenance as a no-shortcut item and no airline will want to be seen buying self certified aircraft.