I agree with the other comments that Google definitely has sacrificed search quality "at the altar of ad revenue KPIs".
However, I think your comments are fundamentally incorrect re "The original PageRank algorithm was more resistant to low quality content - it was fundamentally about a reputation web of trust. As Google shifted from valuing high quality sources referring to you to other signals, it became more gameable."
PageRank became unusable as a primary source of quality long ago due to stuff like link farms and the like. This is a classic example of Goodhart's Law, https://en.wikipedia.org/wiki/Goodhart%27s_law.
Again, I'm not saying Google couldn't have done better by focusing more on search quality and less on ad revenue, but the idea that the "reputation web of trust" can't be totally gamed by extremely motivated spammers is just flat out false in my opinion.
Right, but this gameability could have been improved leaning more into reputation scores across the pagerank-style calculation. Yes, this means some manual curation, which Google is allergic to, but it's also much cleaner long run.
I agree Goodhart's law is inevitable for Google search, but it's very hard to game "high reputation human cares about it". The high reputation human has to be bought out, but that should also eventually trigger a downrank of their reputation as a response.
However, I think your comments are fundamentally incorrect re "The original PageRank algorithm was more resistant to low quality content - it was fundamentally about a reputation web of trust. As Google shifted from valuing high quality sources referring to you to other signals, it became more gameable."
PageRank became unusable as a primary source of quality long ago due to stuff like link farms and the like. This is a classic example of Goodhart's Law, https://en.wikipedia.org/wiki/Goodhart%27s_law.
Again, I'm not saying Google couldn't have done better by focusing more on search quality and less on ad revenue, but the idea that the "reputation web of trust" can't be totally gamed by extremely motivated spammers is just flat out false in my opinion.