IMO, nostr solved these:

1. censorship (noone can stop nostr)

2. misused recommender algorithms (incentivising violence, conflict rather than value)

3. bitcoin/lightning user experience (thanks to zapping, transacting Bitcoin has become a daily habit); medium of exchange

#3 may have greater implications as when you consider millions of people using lightning with ease and speed it offers, there may not be going back to banks, fiat.