Twitter is not going away until newsmakers en masse stop using it. I don't care how much print/broadcast news you consume, if you want a finger on the pulse of what everyone is talking about, Twitter still has the widest reach of anything out there. Looking at it from a business perspective, there is no way celebrities/brands are going to compete with you and me for attention on a platform like CoSo. A significant amount of social media users will always want to be an audience for the famous.
I've seen those same types of accounts popping up on here and they quickly move on once they don't get the engagement they are used to receiving. Things will level out eventually and people will land wherever they get the kind of fix they are looking for. Until then the internet is going to be a wilder west than we have been accustomed to.