> What's Kagi doing differently to be able to succeed?

Define success? It outperforms every other search engine in terms of quality of results and at least from what I understand, they're not too far off from breaking even on their salaries.

Neeva was a VC funded abomination and it showed, they even had deals with "big brand" companies like LastPass to offer bundles, but their core product sucked. Neeva search results were often worse than Google. That's not the case with Kagi.