News outlets use AMP because they get pushed out of the carousel if they don't. You have the cause/effect backwards.
Looking at my Google News feed, I see articles from The New York Times and NPR listed prominently in the carousel, and yet neither use AMP.
Edit: NYT does use AMP: https://www.google.com/amp/s/www.nytimes.com/2018/09/06/us/p...
News outlets use AMP because they get pushed out of the carousel if they don't. You have the cause/effect backwards.