We can't control how implementers code. This is nostr. There is weird stuff everywhere. There are evil relays tracking users, evil clients tracking users, relay devs not knowing any better, clients not knowing any better. Most of the nostr code out there doesn't even think about privacy. We can't design a protocol expecting that everyone will have good entropy, good code or an authed service. All we can do is to offer primitives that makes sense even if everything else isn't there.
Everything you said has been said during the NIP-44 debates and they culminated with NIP-44, NIP 59 and NIP17. But feel free to offer an updated variant of all of the above.