Looks like you didn't get the nuance of the way I answered, I specifically stated creating a google.com equivalent is a big challenge. Either way, OPs statements were poorly phrased, too. A search engine consists of a lot of moving parts. Indexing is not a challenge too great for a solo dev, I've done it myself several times. Crawling is not too challenging for a solo dev, done that, too. A web frontend for the actual searching of the index? Trivial.

Doing any of this at google.com scale? Not happening.

I suggest, like you, OP look into niches. That's how you can break down every one of his 3 statements.

A search engine that specifically rules out every mainstream site? I'd be into that. A search engine built specifically for devs? Again, great. A search engine for blogs not built on Wordpress? Great. An academic search engine? I'd like that, too.

I agree, people are attached, but there are ways to mitigate, at least Duck is trying with their bangs.

A better way to mitigate is creating a niche, like you're suggesting, which is what I only hinted at. Even though I am attached to a particular engine, or website, I would use, IN ADDITION, niche engines.