From a literal sense not using PoW (NIP-13) on most free relays. Find the PoS for paid more accurate. Free relays like Relayable are more like Proof of Hope (PoH) since hope nostr grows, hope spam preventions work, hope can pay the hosting bills from donations... 🤣

Paid relays are as equally unsustainable as free ones since majority are one time fee. So over a year or exponential growth would still come up short. Right now we have about 5 to 10GB of traffic per day to each of the 6 geo relays we have. It grows by 25% each week. Brazil relay is more like X 50% a week.

PoH