I am waiting for the moment relays become just pubkeys (still need some IP somewhere, though).

It's ridiculous. It's all in the name of "easy"

It doesn't seem that complicated to achieve with IP addresses listed in a nip65-like event for relays and pubkey support in nip65 events. I doubt clients would see implementing it as a priority. It would be a fun project to make a PR for it in 20+ clients.

Yep, it's really easy to setup. Then relays just need to accept connections via IP directly. We could start with just wss://<IP> if they want.