DID is a disorder that deeply affects a person's life, and they will need help for the rest of their lives to maintain themselves. It's a very disruptive disorder insofar as maintaining relationships and jobs as well as day-to-day activities. It's often very confusing, involves memory loss, fugue states, and impulsive behaviours. Presumably, someone with DID isn't going to be posting videos about it - although if it isn't severe they can definitely function and treat with psychotherapy - but it would be humiliating and difficult to manage broadcasting that information to the world.
It is my opinion that the uptick in DID cases has to do with attention-seeking behaviour. I knew a couple people that claimed to have it, but it never came up or interfered unless it was to their benefit.
Actual DID cases aren't so much like switching persons in the sense that you alternate souls and become someone entirely else. Instead, it's a coping mechanism formed from a lack of guidance in early childhood. Children (and later adults) don't learn to manage their emotions and/or trauma and so separate things into different personalities to make the discussion, experience, and memory more comfortable and palatable. The definition changed from Multiple Personality Disorder/Split Personality Disorder because it's a misnomer. Dissociative Identity Disorder means using different identities to dissociate from events, trauma, and emotions.
If you want to understand a bit more of the history of DID in therapy, I highly recommend this video. It's 50 minutes long, but it's a good one to just listen to without actually watching it.
