He actually is wrong on this and his recent footnote. Not every last word, but you don't get more money with YT red if your watch time is longer.
There also is another system in play. I notice you can get a crap ton of ads based well bigger channels vs smaller channels. There is some favorably in the back end, or the chance of you seeing an ad is increase based on how many people viewed since the last ad played. (I think there is some favorably more than the other. If I remember right, the bigger the channel the more higher end ads will show up. I remember learning this when Pie lost his favorably)
I don't mind there being some favorably between one channel vs another, but I hate how YT doesn't communicate with the channels. I've been trying to grow my channel since 2011 or 2012, and I'm almost at 10k subs with no views. One of the last videos I made even had regular videos questioning YouTube on why my channel gets so few views and what not (link below as evidence). It would be nice to just have someone at YouTube to give me a heads up on what I need to do to my channel to help it grow beyond tips everyone gets on thumbnails, titles, etc. (From listing to the bigger channels, many of them are told by YT to "get good")