This is a feedback loop though. It is a reflection of the moderation wars in some ways: Google’s main job now is to try to keep you away from malicious sites as much as find good ones.

So they prioritize ‘known good’ sites (big platforms, major companies, etc.) over unknown, individual sites. Then, since it’s now harder to be seen as your individual site (and less work), this pushes people to move to higher ranked platforms. This increases the ratio of noise (the ratio of spam/malicious sites increases compared to good ones) making it worthwhile to skew more towards results from platforms, etc.

Platforms also have the benefit in that it’s a lot harder for a YouTube video to be malicious, giving them more freedom to take chances recommending unknown content. It still could be hate mail, but at least it’s not going to ransomware you.