Gaming laptops are more of a niche market really, and face a big problem. You cannot always upgrade everything. Even more so then before, laptops are starting to be made with the cpu, gpu, and even memory hard soldered on to keep it slim. Hopefully this is not the case with some laptops still, so you can at least upgrade the cpu, memory, and hdd/ssd(depending on the gpu type and socket, you might be able to upgrade the gpu in few laptops).

The latest laptop CPUs tend to be BGA so no way to upgrade. GPU is mostly on MXM module in the fastest gaming laptops. And the difference is narrowing with the GTX 980 laptop version, overclocked it does about desktop GTX 980 default speed. But the price and weight...I'm pretty happy still with my GTX 680M which is a little faster than GTX 750ti.