Not sure why or how

There's plenty of documentation to be found on the why and how, especially following the 737Max issues: https://team-fsa.com/insights/what-happened-to-boeings-cultu...

> Following the 1997 merger with McDonnell Douglas, Boeing’s robust culture eroded. Subsequent safety issues with the Boeing 737 have put the company under international scrutiny and underscored the profound impact of a weakened corporate culture. As Forbes aptly put it, “Boeing’s current travails about safety issues with the 737 MAX 9 can arguably be traced to the company’s weak corporate culture.”

Or read https://www.library.hbs.edu/working-knowledge/why-boeings-pr... for Harvard's take on the same situation.