re: What’s with all the Navy COs getting relieved?

Who knows what it means in the modern context. The pessimist in me would assume that it's for political/ideological reasons.

However, George Marshall replaced Navy COs at a rapid rate at the onset of WW2. Some of which did respectable jobs in their commands and even had solid track records in actual combat command.

I am guessing as we move into more uncertain international times the Navy is trying to update officers to match updated tactics and equipment. Whatever theater the next major conflict will be the tip of the spear is always the Navy.