Boeing was and is a gigantic company, so they could do it and could do it easier than other manufacturers since the FAA is basically a Boeing department at this point.
They didn’t do it because of comercial reasons aka money in their pockets. Airlines were happy not having to do more training, they were happy, stock holders were happy, everyone was happy!
Which demonstrates the problem. When you have a market that only one or a few players can even operate in, that is bound to lead to this exact situation.
The regulations are so heavy and complicated that the best path to profit is to just capture and manipulate the regulators. Which only the biggest power players can do.
So there is effectively no competition allowed here. That doesn't serve the public well at all. We should like to see a market where many more new aircraft companies are popping up with new designs to prove out. Safety as a top concern, yes, but also a path to profit that doesn't have to involve cheating the system.
