That is of no relevance to the customer/consumer. All of these companies are competing for customers of video entertainment.
of course it is relevant, more relevant than just about anything else. if you are a parent or have GenA family members you know it is youtube and nothing else precisely because of user-uploaded content. tt, insta etc are severely lagging behind and are not competitors to youtube in this regard.
My son (5) is interested in marble race videos. None of the platforms you mentioned have marble races like The Black Cat Gear or Moreballs.