I believe ease of use is the #1 reason people stick to non-federated networks, even the governments.
Email, I send a message directly to a person or a group. This makes the idea of a federated network a little easier to wrap your mind around. I sign up for a Google or Yahoo email service. If I'm a big nerd I set up my own and send/receive email with anyone.
Social networks, I send a message to whoever wants to listen. This is easier to understand on a non-federated network. It also doesn't help we don't have a Google or Yahoo microblog service. There is Mastodon and which Mastodon server do you want? This is why I'm not fundamentally opposed to Threads. I share the general concerns of it taking over and not cooperating with the spirit of federated networks, but if all there is is Mastodon people will continue to be confused.
Take a screen shot of the desktop. Set that screen shot as the desktop background and delete some of the icons/shortcuts.