This is horseshit, Opus 130k stereo is perceptually lossless according to many public listening tests. All responsibility for poor quality rests on the uploader and sometimes on idiotic downloaders that still dare to shit out MP3 in the year 2024.
The codec used for transmission is a tiny part of the production pipeline. Perhaps it is publishers choosing to mostly push lesser quality to YouTube, or videos uploaded before they started using better codecs, or any number of reasons.
The truth still stands that YouTube’s videos (at keast almost) universally have shitty audio quality.
Besides, look at it this way: YouTube can be accessed for free. Why would the publishers want to push a perfect replacement for buying the music on a free platform? They’d make less money.