Journalists like to have a record of their work, and I follow a lot of scientists here who post long threads explaining their research. Archivists and other scholars also want a lasting record of work they do. So if the fediverse isn't for that stuff, they'll continue to be elsewhere.... The counter will be that anyone can start an instance and run it for as long as they want...but there is a cost in time, expertise & money to do that. It's a big barrier.