It's weird how "decentralized" means something different to every individual. Having the ability to choose where to host my images is what I'd call decentralized.
Bluesky goes further with the AT protocol for more general data and algorithms iirc
NOSTR isn't twitter nor IRC, you can take your posts which can contain just about any type of data inside and build an art gallery, a forum or dump for meteorological information.
You can scroll back in the past. It is up to the relay if they have interest in keeping your data or not. If nobody cares about your data, you can still preserve it yourself without barriers for that.
As archivist, we both need to pick our sources manually at some point. Nostr is quite a good tool for archives, since its format is flexible (long term preservation) and can work even fully offline.
I've downloaded an app for nostr and I'm not very impressed with the posts on the main timeline. They mostly seem to spam cryptocurrency ads and bad memes, most of them carrying some kind of American right wing propaganda angle. If these are the kinds of people who are attracted to nostr, I can't say I'm sad to see the nostr project decide not to federate with ActivityPub.
I think it's more that these people are around on every platform; but most platforms create (simple, vote-based; or complex, engagement-based) algorithmic filter-bubbles, so that you can live in blissful ignorance of these people's very persistent attempts to get your attention.
(A good example of an already-established platform that doesn't have this kind of filter, is Discord. If you join Discord servers at random, you'll often get flooded by DMs from bots trying to shove this same kind of content in your face.)
As much as the engagement-based recommender algorithms of sites like Twitter encourage "hate-following" and "doom-scrolling", they do have the nice property of inherently filtering out this kind of spam: these "human spambots" post things that can be predicted by their content to receive literally no engagement at all (since everything similar anyone's posted recently received no engagement at all); and so these spam posts get dropped out of any feed they'd otherwise appear in.
Nostr inherently cannot have any kind of online self-tuning algorithmic filter-bubble like this; such algorithms are powered by a global corpus of "everything everyone is currently posting, and every way that everyone else is reacting to it." Nostr relays only see the "notes" that are passing through them; and they have no idea what downstream Nostr clients think of those posts. So even if someone wanted to build a "smart relay" that does algorithmic filtering, there's no signal to power it.
In any client you have the option to see "everything" that is passing, and it is a lot from just about every topic to the tab where you only see the people you follow.
Next time to a better effort to bad mouth Nostr.