While I have no doubt Boeings business has been cyclical, many of the problems they face today can also be attributed to bad management.
These problems can be linked back to when Boeing merged with McDonnell Douglas, resulting in it's loss of engineering focus:
https://www.msn.com/en-za/money/news/how-the-mcdonnell-dougl...
If you read the wiki page for McDonnell Douglas it reads a lot like the modern day Boeing:
https://en.wikipedia.org/wiki/McDonnell_Douglas
This gives a hint as to how that merger help to infect Boeing (no pun intended) with it's current bad management culture.