Youtube is basically optimizing for their own costs over that of end users by using VP9, which uses less bandwidth but often is software-decoded. So the real an

Youtube is basically optimizing for their own costs over that of end users by using VP9, which uses less bandwidth but often is software-decoded. So the real answer is basically that they can, but it would cost them more. (Of course, the YouTube frontend is also fairly bloated, which doesn't help. There isn't much of an excuse for that one).