Instagram is still massive. Twitter was never that big, it just had an outsized cultural influence because the people who used it professionalized being terminally online.
Facebook is the one that baffles me because the only people I know that actively use it for anything besides Messenger and Marketplace are over the age of 60. The younger ones have never even had a Facebook account.
Threads is the other one; it’s supposedly huge but I only know one person who uses it. I’ve never heard it referenced in any conversation and don’t hear about it on other platforms the way you’ll see a Twitter screenshot on Reddit.