I feel like it's a mix of quite a few things, social media is DEFINITELY a big part of the problem but the monetisation of EVERYTHING is the main problem.
When the Internet was becoming more mainstream around the world (late 90s) most people who put content on there didn't do it for money, they did it just to share knowledge/thoughts or just be part of a small niche community.
This meant while there was less content it was more meaningful, and it got to the point quickly as it didn't need to show you ads etc.
Recipie sites show this perfectly, people used to just post family recipes in cooking forums, now it's all personal blogs riddled with ads splattered between the person's life story and multiple requests to subscribe to related guff.
Ultimately the goal of the Internet shifted from "sharing knowledge/communicating" to "show as many ads as possible". This makes 90% of each site filler to stop you getting to the 10% too quickly, so you get snagged on ads etc.
This is why AI is great for companies, they can put in the important 10% and have it make up the 90%, but it's just adding more noise to the Internet.
Also pair this problem with search engines that now take advantage of the noise to provide "summary" blurbs which mean you don't even visit the sites directly so they don't get the revenue, the search engines do, I think there is a term for this "one click results" or something.
Its such a shame, I loved the Internet from like 1995-2005, you could search for something and get really good information and facts on the subject quickly. Now the same sort of things are lost amongst the filler sites that just aggregate information and regurgitate it as their own, or just out uninformed opinions (maybe even AI results) as content as if it's from experts etc.
I could go on for ages on the subject as there are so many facets to the problem but I can't see any real solutions, it's just a midden heap.