I think there is a very simple solution. It requires no technology, but it does require changing the culture of billions of people. And that solution is to make search a paid-for utility. People pay for their ISP, Electricity and Phone, but expect search for free. The problem is this would be less profitable for Google. Because advertising me a $10,000 computer at $10/1000 impressions that I will buy "for my company" is more profitable than me paying $10 a month for search. Therefore the solution might be to make Google a public service, perhaps owned my multiple governments around the world. Call me a dreamer! Downside to that might be tighter surveillance though :-(

I don't see blockchain as a knight in shining armour here. Search is one of those hard things. Like sending a man to the moon. No one can compete overnight. Maybe the hope is AI could create a scenario where a search engine running locally is realistic (like all the prompt-based image generation stuff that has come out, can be run locally now).