That's the big problem here. All the new search engines rely on the infrastructure of the old ones. It would take very little collusion between Google and Microsoft to crush something like Kagi. And the moment any new competitor gets big, they'll do it.
What's needed is an anti-trust breakup. There's simply too big a conflict of interest between Google, the search engine product, and Google, the ad-tech giant earning money off the websites.
Google is using their search engine monopoly to control the wider web, and fill it with spammy SEO garbage to juice their advertising revenues.