Relays that want to aggregate can and will aggregate. I don't see how that will "break nostr or make it way worse" but it eventually won't scale. So long as it is "pull" and not "push", and so long as users don't become comfortable using just a few centralized relays.

Relays that don't want copied events should require AUTH for writing and only accept events from the event's author... they don't have to require payment, just authenticate who is pushing the event.