IMO, I think google was never designed to really drive people to highly detailed resources. Google is more similar to something like wikipedia where it gives you the high-level overview instead. It makes sense as well that it is like this because the vast majority of people want the basic information, not super detailed information, so over time most of the authoritative sites (sites with tons of backlinks) end up just being sites that are "overview" sites, not a comprehensive resource for the subject.

That's why there is still value by going to someone who is an expert in the subject to basically curate the information for you....like in a course. The problem is most of the experts in the subject work for universities and have no interest in giving their services away for free or the people that do are only able to give a basic course in the subject (coursera, udacity etc.) with limited resources that make self-studying the subject difficult.

I think we need something similar to YELP but for online courses that can be used to self-study. There might be 100 online physics courses but no one really knows which one is "best". Some might only have a textbook, others might only have lecture notes and then a few might actually be very comprehensive....but no one knows this unless there is some sort of review/recommendation site to use.