They don’t have to take energy to adopt the format. You do realise that current ActivityPub services don’t support all services and features of the other platforms? You realise a great deal of Fediverse utilises Mastodon’s implementation of AP? So a lot of what people are worried about Threads doing has already been done by Mastodon.
It was just an example. The same can happen at the Mastodon-level instead of the Fediverse-level. Since there is some desired interop (e.g. between Mastodon and Lemmy), services do influence each other in their feature set.
I’m not sure what you mean by “a lot of what people are worried about Threads doing has already been done by Mastodon”. Do you mean that the decisions that Mastodon make influence the rest of the Fediverse? If so, let’s make sure we understand the difference here: Threads has a much more hostile disposition. Mastodon seems to have incentives aligned with the rest of the Fediverse services, and probably deserves the benefit of the doubt; Facebook has abused that benefit time and time again.
