Member napstr? it almost sounds like nostr :) We may see relays evolve to be p2p, synced with negentropy or simply streaming, and over onion or something in the long run. The differentiating factor will then be what to include in the relay (a.k.a. spam filter and filtering based on reports).
Discussion
There could be specialization of relays like long term archive of notes (big hdd), file storage (ssd), web (fast cpu and nvme), streaming or nostr hub (10g ethernet), real time communication or notes, kind of like current nostr (big ram).
NIP-94 is this already. Nostr is the ultimate torrent tracker.