@luca We're saying the same thing but I'm not sure about the details. Perhaps the optimal size for storage is closer to 1000 users rather than 100. I'm not sure I'd call 2 TiB of storage (the average in the Jortage pool) "minimal". It's still much better than 100 (what they'd need if each member of the pool mirrored everything).
Recently #mamotfr started purging old media and posts with the extremely broken https://github.com/mastodon/mastodon/discussions/19260 . It's not clear why, perhaps limits in PostgreSQL scaling.