I think it's both in a sort of chicken and egg sort of situation. The MD execs taking over Boeing had a terrible effect on safety culture, but the reason the MD execs took over in the first place was because of this shift in the market that you describe.

If the pre-MD Boeing management had managed to retain control of the company things may have been ok from a quality and safety perspective... but the stock would have declined because they would have refused to chase short-term quarterly success at the expense of the long term.