I am very well aware of the appeal, but:
1- I don't have to make Nostr architecture my base just to use free pub/sub. I can just take advantage of it when I need, especially that friction and costs are zero.
2- if all I need is 1-1 relay, then there is also the competition from SimleX, which is definitely more private, so Nostr now is best only for many to many broadcasting.
3- there is only so much I can do with ephemeral data, and I want persistent and more importantly e2ee, nostr is not made for that, and that can't be done without increasing Nostr complexity, ok but whatever data store will hold my data persistently, it can also double as ephemeral open pub sub if ever needed. Especially with pkarr when I KNOW where my contacts store their data and can send them messages there, or fetch their latest public notes.
Nostr relays may very well end up being the RSS of this ecosystem, the aggregators and feed generators that people subscribe to to get a precompiled view, which I feel Fiatjaf is trying to cement as the way to use Nostr and I full agree with that, but it can't be the infrastructure for what I want, not without ruinng its simplicity, case in point, you could have built NosDav over relays, but it would be a bad idea.