In the extreme case, doesn't that degrade to essentially having to connect to one extra relay per person that we follow?

Bitcoin nodes talk *to each other* and share data so that they're all ready to share that vital info with a client (i.e. your wallet app). But Nostr relays don't gossip w/each other afaik; they can only broadcast what people have directly published to them.

The only time notes get propagated out to further relays is when someone boosts it to all of their connected relays, right?