The average registered youtube user is a random person that just watches the occasional video and had to get registered because on of the videos he wanted to see was adults only. The average registered youtuber does not give a flying f#$% about analytics of the random video he watches.
So would one percent pay for a monthly fee? Doubtful. I think the author thought they would simply because one percent is a very small number.
But it might be a good idea nevertheless. It is good idea from the business perspective as it is not likely to prevent people from using youtube in general. A person will usually first upload a video and then worry about who is watching it. So the fact that youtube charges for analytics is unlikely to prevent anyone from uploading videos.
So good idea, but it is very unlikely to bring in the enormous amount of money the author imagines.