Vance is Peter Thiel’s hand puppet, just like Trump is Musk’s. Thiel and Musk first came to serious money when they merged their companies to create PayPal, and since then they’ve been cooperating on various projects. Their current project is to establish corpo-feudalism in the US, and for that they need geopolitical isolation (Thiel’s job) and the dismantling of all social safetynets (Musk’s job). That’s all the context needed to understand Vance’s behaviour.

Most likely answer is that they do it for the same reason as Facebook not sorting their feed by date: they want users to fully rely on their algorithm. My completely uneducated guess is that they want to feed their users older videos where they don’t pay out as much to their creators as they do for new videos.