1. The lens elements are really large to gather a lot of light so that it can work well in a wide range of lighting conditions. The front most element is as large as the front hood.
2. Every set of lens elements, some being just one lens, is moved individually, there is a controller that calculates the proper position for each lens and moves them based on input from the operators controls and the camera. This allows the lens to zoom really fast without loosing focus.
Edit: In my experience, the mass of the lens is not as important as the tripod head when it comes to keeping operator shake to a minimum. A good head will smooth out the operators movements and a bad operator is perfectly capable of making 100lbs of camera and lens shake.
I think I was just making sure it was clear (to others, since you probably are aware) that it's more than just lighting/apertures. Being good at a variety of lighting conditions, and being able to do that from 18mm-1700mm with a variable speed zoom without losing focus is where things get really big. There's a lot of features in the camera body to support this specific type of production beyond the lens, too. For live TV, an operator is making split-second decisions around composition (including adjusting for graphics on the screen), lighting, focus, and movement, while also monitoring on-air status and listening to both director and (sometimes) program audio. And then you have to add on the massive rigs that make sure everything's in perfect balance so you can whip the camera around quickly and have it stop on a dime. It's a whole system. A good high-end rig is like driving a Porsche. Sure the engine is a big part of the power and engineering, but if you don't also have a properly tuned suspension and grippy tires, you aren't going to have much fun driving it.