When legacy media companies sell ad space, often they do not do so through an auction mechanism but through a direct purchase model. That means someone paid anywhere from a few hundred to thousands to be on that page. That gives them more of a client relationship and so they can feel more burdened to make sure advertising clients get 'visibility' and bang for their buck.
Also, they can sell ads in their videos with estimated view/impression counts. If they autoplay, the view count goes up even if you're not watching the video so an unsophisticated ad consumer thinks the ad spend is justified.
I don't run ad campaigns anymore, but I did for eight years and I always preferred no autoplay because intentional viewing is much more valuable for what I was selling.
Use adblock.