I’ve been using the web before it was the Internet that spawned outside of the university systems here in the US.
I became a web developer and spent almost two decades in this field.
There is one overarching aspect of websites that keeps people coming back and engaged.
Namely, high quality content. The search engine algorithms are written to find it. The humans that use the Internet want it.
Yes! Sharing links is great but it’s original posts that really make a difference on social platforms.
Although I’d agree with this statement, people here occasionally use hacker news as a reference, which also has almost no original content. Nevertheless, the overall quality of the comments there is much higher than on similar platforms, which is the main reason for me to use it, apart from the variety of sources and the number of prominent members. So, in my opinion, it really comes down to what OP mentioned - thoughtful and varied content is the key.