I’ve not used it, but have heard decent things about Kagi, a paid search engine. Supposedly, it finds things like how old Yahoo or old Google worked, without AI (but is optionally available?), and no ads.

I would think the major barrier to entry is the business model: ad revenue goes to those that can deliver results. Google AdSense has dominated that realm for years, so it would take a major upfront investment to challenge them on that. No much different than how it’s hard to compete with established airlines to a particular airport that they already serve. Economies of scale tend towards consolidation.