This made me think of the ad business on Twitter which I think might be its real killer.
If a community builds up on Threads (and why wouldn't it, reserving spots for 2B Instagram users?), the ad value will then probably be much greater there, and businesses (and thus influencers) will see a more lucrative environment there.
Why?
1. Meta harvests more data from your phones than Twitter which provides more accurate ad targetting.
2. Twitter is poorly ran and struggles even with basic things like not pissing advertisers off as they keep making controversial decisions for the network.
The news of rate limits must have spread like shock waves through the ad community, as one example. Reducing reach by now walling their garden and killing embedded tweets to make it harder to get to their ads another.
As for celebrities, they already have good community contact on Instagram since the visual medium lends itself extremely well in that regard, and I'm 100% sure Threads will ultimately become an extension to Instagram.
Isn't it funny how Elon has hunted his X.com idea for a "social network for everything"?
Instagram is far ahead than him now. They have Instagram photos, Snapchat stories, TikTok reels, and now Twitter threads.