I definitely agree on your points about the majority of the web being low quality noise. Not just in a "humans produce garbage" sense but also that various SEO and marketing techniques have created a sea of automatically generated nonsense content that search engines now have to wade through.
I also find searching for anything remotely niche has become extremely difficult because of this. Example being finding instructions on how to install some bike parts today. There were articles about the specific parts eventually, but only after significant iterations of my search terms and wading through all the matches from people targeting those keywords to sell product.
I feel like Google specifically are failing to wade through the sea of noise, and as a result it's becoming less and less useful.
It works well for things like programming troubleshooting, because we have high signal resources (stack overflow, for example) that often have the answers we need. But for anything outside of developer specific topics I usually have a really hard time finding anything useful and not spammy.
I now rely on having stumbled on some good sources, and sticking to reading those, rather than googling subject matters these days.
HN, Reddit and various news and tech sites curate content as you said, but the problem is that this creates a bubble and the beautiful world of exploration and learning that the web was all about disappears.
I am excited to see how we solve this problem, and who solves it.
In regards to Google Search going away, I feel like even if their search engine failed, the AdSense network would live on, and that is where the majority of their income comes from.
I'm not sure if the majority of it comes from Network ads (ads displayed on other sites) or search ads (ads displayed in their search engine). That might be informative of where they plan to focus their energies over the coming decades.