To be fair, many Nostr devs realise that spraying and praying data on relays isn't sustainable for most use cases, and the Outbox model seems to be a step towards people entering a relationship with a specific home relay.

But if we take that to its extreme, then if the few big relays are only serving to facilitate  discovery, then these Outbox relays could be better as HTTP api servers not websocket. Blossom seems to have opted for that which is good.