@iamlayer8 the main issue that prevents this from being the case is that Mastodon (and the services that preceded it in some part) unified the client and server parts of ActivityPub.
Ideally an ActivityPub server should be able to accept multiple types of activities for different purposes and different clients can make use of different resulting objects. Ie, a Mastodon client can display textual objects in a twitter like format, a Pixelfed client would display image objects, etc.