Speculations by people hoping to get a grip on the unknown.
But lacking evidence to the contrary, just as you say, first guess should be some failure of command.
When I was in the USN, we had a 600 ship navy. When you reduce the number to less than half, you eliminate many opportunities to acquire experience and training before assuming larger commands at sea. It resembles an apprentice system. Add to that an unreasonable operations tempo that strains the fleet. This is a symptom of much larger problems.