Yes, and I suspect that's the aspirational model that is used by most. But ultimately they are at the mercy of Google and Bing's terms when they use their data.

Yes, and I suspect that's the aspirational model that is used by most. But ultimately they are at the mercy of Google and Bing's terms when they use their data. Realistically DuckDuckGo, Qwant, Yahoo, Ecosia, Lycos, etc. won't just shut down their businesses if they feel that Bing crosses a privacy line in the sand. And neither will Startpage or Ask if Google do the same. Follow the money and all that.