

Discourse already exists (and most big companies use that).
Also you can see many other things on Reddit or Discord too (or the internet). Im not sure how that is a point against federation. If companies really want to control everything they can create their own instance (like KDE’s lemmy instance).
They can defederate everyone from their instance to get an “unfederated” instance but again it changes nothing imo.
In fact defederation is a negative since now you have to worry about new signups, moderation, etc. While in a federated instance, you can leave moderation to other instances and only allow team/company members on your instance. Users can sign up on other instances and still be able to interact with your instance for support, help and other stuff.
Subreddits were not a problem before since they were accessible on the web without needing an account. But now reddit is gradually locking them down behind authwalls and things like not letting search engines index (other than Google).
Lemmy communities dont have this problem and because lemmy is federated, its resistant to such enshittification (plus you can easily create your own lemmy instance for only your team). So imo they are a good alternative to forums (and reddit) and a good solution to this problem.