That money gets you a NVIDIA GeForce GTX 1070 (thin and light) laptop.
Those are really different markets and devices. Yes, you've always been able to get higher performance for less by sacrificing other aspects of the device and build quality. But, ultrabooks aren't really aimed at the dedicated gamer market. And, thin and light is relative. Those "thin and light" gaming notebooks are still 50% heavier with an inch or two increase in pretty much every dimension. And at that price you're looking at a 1080p screen (why do you need a 1070 for that?) vs the 4k screen you're getting in the ultrabook. I would HATE to take those things on business trips or attempt to do work on a plane.