Scale is a fiction invented by SV to capture and control the market.
It is healthy for nostr if big relays are difficult to run. It helps prevent centralization. By design, no single relay will ever achieve “twitter scale” and that’s a good thing.
It helps prevent centralization.
No it doesn't. A single, very expensive, computer can probably run all of Twitter. There's entities out there who will step in to run those very busy nodes... but only a few entities. That is a clear centralization problem.
Your argument would only be correct if the scale was so enormous that no entity could handle all the load by itself. Which is certainly not true even on the individual computer level, let alone with clusters.