https://www.google.com/search?q=link:http://www.plausiblyden... revealed 370 results, including social networks, blogs and the like.
What may be true is that the global signal to noise ratio is lower than before. A consequence of the web being cheap and accessible. However, that kind of content is not only present but there is more than before. And while it is buried under piles of noise, we have much better tools to deal with it.
Search engines like Google, Wikipedia, Hacker News, etc... will get you loads of quality content. Platforms like Twitter, YouTube, Reddit, etc... can get very instructive if you follow the right accounts, or give you some mindless fun and memes if you so choose. The two are not exclusive.
The pyramids are an example of this distinction.
However I think, from your examples, that you see the world in a fairly similar way to @le-mark and your distinction is more one of labels than anything else.
The pyramids were never lost. They were in plain sight the entire time. Local people knew about them. They were 'discovered' by European colonizers and integrated into a pop culture phenomenon back in Europe, which included racist tropes and undertones.
I've heard people say subreddits have taken the place of these things, but whenever I look, they have already converged to the most nanoscopically narrow idea of the respective scope. There used to be more wiggle room for authors, and surprises for readers. Now it's all writing to a well-defined audience, genre, or meme: KPI-driven socializing. In that sense, web 1.0 seemed more fluid and interesting.
Five AMAZING geek social fallacies you never learned in school. You wont believe number 4!