The problem with DID is that it’s not what anyone thinks it is.
I personally maintain that all mental disorders are windows into the function of the brain, in the same way that someone getting a nail driven into their skull resulting in a gross personality change tells us about the brain. Obviously SOMETHING is no longer working properly, but a more interesting thing to contemplate is what the normal functioning in question actually is and what it is actually for.
There’s a lot of talk of PTSD and retreating into another personality to escape trauma, but I feel what goes on is more similar to the dissociative state when we dream. That’s the “normal function”, the dissociation that occurs in completely healthy people. We dream we are in places we are not, circumstances we are not, and people we are not, acting very unlike ourselves. Doesn’t happen in every dream, but when it does there is nothing to be concerned about. But when stress and trauma leave the more surface level conscious mind at a loss, the subconscious mind - the one that does not shut off when we sleep, and continues to think and work at puzzles during the night - gets involved to problem solve. Thus the dissociative state. The goal isn’t two create a bunch of headmates like the tumblrites want, but to get every part of the mind working on ending the stress and trauma; which results in problems that illustrate why we have our minds split into surface and subsurface as we do.
That’s just my theory of course, and we’ll probably never be rid of the pop culture interpretation or the Fruedian “he’s just hiding his trauma” explanation. Catatonia is what hiding looks like, not DID.