LOL, what? My brother, this is like using a microwave an complaining it doesnt brown your pie. Don't blame the pie, you picked the tool.
As I had to have crammed into my understanding a few times, all ActivityPub posts are in fact the same, they are completely interoperable, it is only the Instance and Client which determine how you can interact with that content.
If you use your instance webclient as the only way to interact with ActivityPub content, you are choosing to defer the decisions of how you interact with the content to your Instance admin. It's not a FediVerse problem, it's a you problem.
Also keep on mind many Clients, including Insterstellar and FediLab, allow you to log in to multiple accounts on different instances and switch between them easily.
If you want more features, use a broader based client, and subscribe to the users/communities on the instance you like to keep continuity of content.
I just read through your article in detail rather than skimming, and what you outline is perfectly mirroring my current sentiments. I just posted a post asking a related question: why build ActivityPub instead of feature rich clients built on-top of existing protocols like RSS/Atom/email which are already built around self-hosting?
There is something about the server/instance intermediation of ActivityPub that strikes me as antithetical to the goals of distributed social networking, but I do understand the advantages of offloading moderation and server admin to specialists. Instance as nexus for message routing is an interesting way to look at it, I have been thinking of it as Instance as Aggregator, essentially providing group moderation and directory services but offloading all content distribution back to the host/client format of the open web/blogosphere. It would solve the authorship issue among other problems if Syndication was actually just linkback to the original host.