They are computers
Capping the power usage of a computer is a stupid idea, and I'm a hippy green loving environmentalist.
The only thing that happens if you cap power usage of such a device is the functionality will not be as good. Ok, yes, CPUs and GPUs are regularly being released with new capabilities at lower energy ratings, but these things take time to be developed and to reach the market. The legislative machine moves even slower than that though. They've been negotiating this agreement for 6 years! In that time, there have been, what, 3 generations of Intel CPUs?