In my opinion, Muilenberg didn't have another choice in acting, as he had had in the MAX crisis!
I work a lot with large corporations and nowadays, especially in the US, the CEO's do not have much power in steering their companies anymore. I am sure, Muilenberg was advised / forced by Boeing's legal team and the board member how to react and act in every minute!
CEO's have to obey the internal guidelines, advisors, board decisions,... and are not anymore entitled to a strong personal opinion and even announcing their opinion in public. They don't want to be exposed and are afraid of making errors when not double checking with their legal team.
The main problem for Boeing (and many large US companies) are not the CEO's, but the corporate and legal culture of our time. There are less and less "leaders", trying to change a company completely or even admitting mistakes and apologizing, as this might affect the stock performance.
I fear, not much will change at Boeing by changing the CEO ... the change will just happen by public pressure!
DC-6, DC9, Do228, Saab340, Twin-Otter, C212, Fokker50, AN24, MD90, MD83, EMB120, A380, A300, A343, A346, B721, B742, B744, B748...