Except at no point did the regulatory environment change for Boeing in ways relevant to production - the rules actually got easier. Majority of 737 is produced

Except at no point did the regulatory environment change for Boeing in ways relevant to production - the rules actually got easier. Majority of 737 is produced in USA - with many critical subcontractors being former divisions of Boeing that got spun out because, paraphrasing "We will concentrate just on adding value in the final assembly step as well as coordination". It was explicitly done by the upper management, despite everyone pointing out it was bad move. Airbus also does a lot of subcontracting, but is way more integrated and reportedly works on "risk-share" basis with contractors while also providing considerable amounts of resources to ensuring the whole chain is safe and sound. Those are management decisions. P.S. a lot of regulatory decisions that block things like building infrastructure including housing are driven by "stockholders" that would be involved, because they sometimes perceive investments as endangering the existing value of their capital.