The elephant in the room is that we made requirements for getting a completely new plain design into the market so expensive and time-consuming, that Boeing cut corners and reused an existing design to get around the process.
Boeing introduced the last new airframe for commercial passenger transport on 2009 (the 787). Before that, it introduced the 747 in 1994.
Which new airframes that enter the market all the time are you talking about?
Boeing in particular was under pressure from the more fuel efficient Airbus A320neo, and they needed bigger engines (larger fans) to compete on fuel efficiency. Those large engines don't fit under the 737 airframe, but getting a new airframe approved is time-consuming. So Boeing placed the bigger engines more forward from the wing, resulting in flight instability and pitch-up.
Boeing tried to fix that problem with software, but, as became apparent recently, weren't very successful with it.
I'm pretty sure the requirements are fine, but the process is not streamlined and hence avoided whenever possible.
You don't get to stay in business in a regulated industry with an attitude like that. What's next? Medical device manufacturers cutting corners because the regulations are too onerous? Regulations create a level playing field: all entrants get to abide by the rules. Or at least, that's how it should be. The FAA turning a blind eye here is as much a part of the problem as Boeing.