Design is often influenced by our habits. I sometimes feel that people now use "apps" as containers. They separate their @pixelfed life from their @writefreely life via the applications.

As such, it sometimes feels like people do not want an all encompassing feed. I think it would be pretty cool, but it feels like developers don't even consider it. In the capitalist model, you have to build your brand, use my #activitypub thing, not others!

A better reason is that each separate post type is an entire paradigm to integrate. It's often better to do one thing correctly than several poorly.

still, the possibility to have a single identity across multiple platforms would allow the fediverse to have both the quality of software that “does one thing and does it well” and the possibility to “unify” content streams at the user level.

This sounds to me like OpenID or some other kind of identity provider, not an encouragement by any specific platform to support any more post types than they initially set out to.

My initial response was motivated by the software I'm working on, #Friendica. We offer formatted posts (correctly), photos albums (poorly) and events (poorly). We are able to display PeerTube videos (acceptably) in your content stream but no polls yet (work in progress). Even posting pictures is somewhat an adventure on Friendica, while it's a breeze on Pixelfed where it is the main focus, for example.