100% agree on the point that there's now space for niche search engines. I don't think a search engine for everything is a viable goal (there's too much crap to sift through), but I do think there's space for smaller search engines for particular domains.
Even better, make them somewhat curated by domain experts so that users are served high quality content and not just low quality sites that magically rank high because they managed to tick all boxes in the ranking algorithm.
Even better, make them somewhat curated by domain experts so that users are served high quality content and not just low quality sites that magically rank high because they managed to tick all boxes in the ranking algorithm.