That kind of manual intervention doesn't scale though. The only way it can work is to have community-curated lists of bad domains, similar to adblock lists, that users can upload to personalize their search result.
Somehow a distributed community of unpaid volunteers manages to keep the entire advertising industry (where billions are at stake) at bay by curating adblock lists. I'm sure a company can achieve the same. It will never be 100% perfect, but it will surely be better than what we have now.
But yes, supporting community-supplied adblock-style lists would be a start, and Google isn't even doing that.
