Laptop Power Draw

I know laptops normally have power bricks around 80W. However, I was looking at my laptop's battery and it is only rated for 37 Wh. So theoretically, that means it could provide 37 watts for one hour or 1 watt for 37 hours. Typically, my laptop last 4+ hours, so that means my laptop is only pulling 9 watts.

How is this possible? Run a cpu, motherboard, and display for only 9 watts.

The reason I even started looking at this was because I am tossing around the idea of making a mobile desktop. But it seems even if I get 35W cpu, 60W GPU, and 25W monitor, that is 120W. So I would need a 480 Wh battery! I realize my laptop doesn't have a gpu, but 9 watts is damn low.

Out of curiosity, how long does high performance laptop run will full battery and fully loaded?

Laptop parts are specifically chosen for low power usage. The CPUs are designed and binned for it, so is the RAM, the GPU, the hard drive, everything.
Keep in mind that if you actually use the CPU/GPU you'll get far lower battery life as you'll be drawing significantly more than when you're just browsing or working with text.
Along those same lines, the 35w desktop CPU only uses 35w at full load, at idle it uses a lot less.