I think achieving this would be worth billions, at least?
We really tend to underestimate the amount of spam on the internet.
Google does badly here: it overcorrects and you get only super safe results. Yandex? Unless you get lucky, lots of spam.
You'll still get spam if that's all that matches your query, but now all it takes is for someone to make a page matching the query without the aforementioned items to outrank the spam results. You wouldn't need to append "site:reddit.com" to your queries because the (mostly) non-commercial Reddit results would automatically outrank all the blogspam and listicles.
If ads were downranked it would make a lot of spam/clickbait/listicles unprofitable overnight as they'd rank low enough that the costs of creating & maintaining the spam site/content would outgrow the returns from ad impressions.
This would be a really interesting experiment: A search engine that ranks websites by the amount of Ads and other spam that they contain.
SEO is killing Google and it needs to be addressed before it kills the internet. Having the opportunity to build an app that solves a search, instead of perpetuating a spam system, has been really rewarding... and we're just getting started.
I've been trying out Kagi as my default search engine, but will give You a try next.
I'd pay /mo for a good one. Why not? Currently trying Kagi.