I don't have an answer this this directly, but it does follow the trend on Youtube. It's best to see the history of its like-dislike system. First, it was a 5 star system, then it devolved into a green-red bar, then a blue-grey bar, then a darkgrey-whitegrey bar, and eventually the formal removal of the dislikes.
You will definitely notice a stark difference between 2007 youtube, 2011 youtube, 2015 youtube, 2019 youtube, and 2023 youtube. This a 4 year interval, yet each one, especially the HUD, feels like a different era. And the changes are not for the better. And I know for a fact that Youtube isn't the only one, but I chose this bc it's the most well-documented, courtesy of Emperorlemon (Also known as admiral ackbar who made the Never Ever series).
I cannot be definitive on the general trend of updating HUD. Maybe it's coding issues, maybe it's updating for modern audiences, maybe it's the preference of Doggiebones. Again, I cannot be definitive here.