So, finally a paid search engine that does not have to rely on ads for revenue.

So far it's based on Bing, which does. This makes it a bit a hard sell, compared to an intelligent ad blocker.

The most important problem of search engines is SEO spam. Google themselves sort of have a moral hazard to not be too stringent on SEO spam, because it shows ads by Google, increasing Google's revenue.

OTOH I wonder if the subscription revenue is going to be sufficient to have access to a reasonably good search index and enough processing power to efficiently combat SEO spam while returning relevant results. This takes your own data centers run frugally, because fees of something like AWS or Azure will just be exorbitant for a global search engine and a global search index.

I wonder if companies aiming to provide alternative search engines will cooperate on maintaining a common index, to distribute the massive costs of doing that. They could even publicly sell access to it, at a point where running a competing search engine won't be practical; e.g. researchers would buy it.