Radically different sorts of business. Youtube's income comes from engagement, and it's value comes from its network effects. Youtube doesn't own any of the content on its platform, and you could replace every video on Youtube and it wouldn't matter so long as it remains the place people post videos. Youtube's survival is about gaining and keeping eyeballs, its competitors are other sites that people may spend their time on. The social media features - the comments, the likes - may not matter to you or most anyone else, but Youtube is thoroughly a social media business. Indeed for Youtube most content is an ongoing cost - they must pay to store billions of videos most people will never watch, and certainly which won't generate ad revenue to cover their hosting expenses, so that they can host the thing which actually does pull a sizeable audience, most of which is ephemeral.

Disney on the other hand is an IP curation firm. Sure they make money on movie tickets and subscriptions and merchandise, but they create value by creating and maintaining a litany of characters, stories, and settings which are priced based on the idea they can be milked essentially forever. Disney could pump out flop after flop after flop, but so long as those flops keep Disney owned characters alive in the zeitgeist, it's a financial win. Obviously Disney needs revenue, but it's valuation is only loosely related to its current revenue.