As ActivityPub is just an underlying protocol, the question is similar to asking something like “Is it possible to make an Internet app for everything?”.

There will be new ways to use the #fediverse in the future and new applications will be developed and adopted and it makes little sense in trying to provide every possible way to view the fediverse in an ever playing catch-up implementation of a view into it.

Try to look at it as the Internet itself.

It’s an attempt at providing a finite and limited answer to an open ended question. Doesn’t make a lot of sense.