[supertestnet]

It's not decentralized yet but only potentially decentralized if a lot of people run relays. Currently there are only about seven relays powering the whole network: https://nostr-registry.netlify.app/

Luckily, relays are very lightweight and easy to run so maybe it will eventually get decentralized.

[pseudozach]

And remember relays can be incentivized to host content by micropayments via Lightning network if needed.