Why do you say that the relays are well incentivized? Aren’t all the current major relays subsidized? It seems that nostr works because Jack and others are essentially bearing the cost. There are artificial subsidies here.
We also need to acknowledge that the client architecture is pushing the community to have fewer very large nodes. Not a good trend.
The first step to fix a problem seems to be to acknowledge it. Then people can brainstorm solutions. Not sure motivational “nothing to see here” posts are helpful, even if well intentioned.