Good point but unlike with Nostr, I can't really think of any deep-pocketed organizations that had a financial incentive to see our landline phone companies fail.
If the Nostr community's commitment to free speech is genuine, once it really starts to take off we can expect an influx of bad actors (both corporate and state-sponsored). They'll use both doxing and disgusting content to drive away users. Even the most thick-skinned defenders of free speech will begin to worry if they're being viewed differently by friends, coworkers or customers for being associated with a network that harbors such content.
I don't know what's the best solution. Every family or neighborhood running its own private relay or Mastodon instance probably isn't going to help content creators who are trying to achieve global reach.