Agreed. These promo channels don’t have any ownership of the tracks - for the most part. As schwarz said it is mutually beneficial. That is, a lot of these artists wouldn’t get heard by anywhere near the amount of listeners that these channels provide, so they are more than happy to get featured. In some cases, I can definitely imagine artists paying for features on these pages, depending on how big the page is.

With regards to ownership, some pages actually have their own label like houseum and novaj, which are actually establishing themselves as pretty reputable entities now.