I believe you've hit the nail on the head, the only people I've noticed that really want such a social media account are generally people who were older than millennial, out of Millennials, gen Z and gen A, I don't really see much interest in a social media account that is directly linked to your actual identity. Most of them are more interested in a pseuado-anonymous style account that only asks for a username and doesn't actually link you to a real world identity.

Facebook was great in principle, it was intended as like a college student community and evolved from there, it was never meant to fill the goal of what the platform is doing today.

As such as Facebook deteriorates, there isn't a huge demand for a Facebook alternative, because the people who are leaving the platform aren't actively seeking to replace what is lost.