Why, if your goal is to save bandwidth, would you have the system default to loading the biggest assets when you can't ascertain these things, instead of loadin

Why, if your goal is to save bandwidth, would you have the system default to loading the biggest assets when you can't ascertain these things, instead of loading the smallest ones? That said, given my experience of running the web with NoScript, I'd be surprised if those sites that double the usage when they can't detect these things come anywhere close to eating up all the bandwidth I'm saving by not loading auto-playing video ads.