But then, as I understand it, Bitbucket was an acquisition rather than a brainchild of the Atlassian team, so you can expect a certain amount of neglect.
An omen for github?
Devil's advocate: why would Microsoft invest in improving, say, the issues functionality of GitHub when it could instead integrate and push users towards its existing products and tools for project management, like SharePoint?
See their GitHub for more:
Also their focus is now on developers. They made VS Code completely free, MIT Licensed and not for themselves, but for developers.
For example, if a Gitlab instance posts a Pull Request object over to a Mastodon instance, what is the latter supposed to do with that? presumably it won't have any UI widgets to display the content, and no way of acting on it semantically.
As far as I can tell, Activity Pub is a way of federating instances of the same application, with the same semantics. But on the internet I'm seeing some dialogue which seems to presume that AP would make it possible to federate instances of all sorts of different applications and have them all Just Work™
(Apologies if I've misunderstood your post, I'm kinda rambling at this point)
For example, GitLab projects could publish their activity feed to Mastdon. You could follow it to see what commits they make, issue discussions, and so on. Meanwhile, federating things like pull requests would happen across Git based services. So, if Gogs decides to implement compatible ActivityPub protocol, then it could integrate into the federation of GitLab servers.
People on GitHub is not just to sharing codes, but also to get in touch with each others. GitHub succeed because it's not only just a free online Git repo services, but also a developer + user community where you can put your code on, share it, and 'earn' stars & forks as feedback. And stars + forks can help you stand out in a job interview and many other occasions.
Bitbucket is another Git repo service, but it sort of failed to build it's community. Result? It received less attentions compare GitHub.
So, while GitLab is also trying to be 'yet-another' Git repo + you can host it on your own, the benefits of become community can't be ignored. And federation can help that by connecting all the GitLab instances together to form a bigger and global community.
Even better, the federation protocol itself can be an open-sourced public standard, so all the other Git repo software can implement that in their product. The potential is huge.