Hmm. There's been a lot of talk here about the Boeing culture vs. the Lockheed culture, and how the Lockheed culture took over after the merger. Yet the CEO was a Boeing guy, not a Lockheed guy.
Boeing and Lockheed aren't merged as companies, they're only combined for building launch vehicles. They created ULA as a joint venture. It was a weird situation where it made sense for both companies— Lockheed basically lost all of their trade secrets to Boeing after they did a crazy amount of industrial espionage. After a few Boeing employees went to jail, Boeing lost all of their launch contracts and were banned from bidding on any for a few years. Even after the ban ended they were in rough shape financially.
Muilenberg became CEO 18 years after the merger. I wouldn't expect him to exemplify Boeing's old culture. It was also only 6 months before the first 737 MAX flight.