You can’t replace videos.
You
can, it's just that only a privileged few are allowed to, and I guess it must be a big secret, because nobody is talking about how it's possible, even though it clearly is. Heck, even SS's official YouTube channel was able to do it at least once with their Tropical 5 upload years ago - there was a noticeable glitch in the video at a specific time point , but by the next day, the video had been replaced with an upload that not only lacked the glitch, but was also in somewhat better quality, but nothing else was changed: the view count, the comments, the likes/dislikes all remained the same.
Not to mention, almost every Topic video has been replaced with new uploads a couple of years ago.