How the heck would you ever enforce this? If someone complains that someone is slow in front of them, do you pull them both over and ticket one for driving too slow and one for speeding? If everyone would just not be in such a hurry all the time the roads would be far safer. And you save money on gas.
Now of course if it's a mountain pass and only one lane going each way and someone is going well UNDER the speed limit, then that's different as they are stopping people from even getting up to the speed limit. And since Freeways have a maximum and a minimum speed, it's going to be hard to enforce anything.