I don't think YouTube has peaked. It is as popular today as it as ever been. It's not surprising monetisation is more prevalent when channels grow. I remain impressed that among the staggering quantity of content there is plently to watch and find. I rarely watch the most popular tech channels.
The trend I dislike is 'shorts' which are encouraged by YouTube. An obvious nod to TikTok, which ironically now allows longer videos - a maximum of 10 minutes.
So to sum up: yes, there is lots of rubbish on YouTube (as to be expected), but there is also plenty of watchable content - whether it's silly, informative, education, music or a myriad of other types. Is it unhealthy to consume too much? I guess that's a question for a different discussion.