It is "necessary" in the sense that AnandTech would be out of business otherwise.
clearly, websites that do this are shooting themselves in the foot in terms of UX, for the sake of pageviews and ad impressions. Is there now better way?
When I worked for a publisher there was a long debate over UX vs page views and ad impressions.
I think Google has rules around how you can load ad's also so it might not be posible to do anything dynamic. Google has all the ad inventory so is the dominant player.