Having no general speed limit needs to be a thing of the past. The speed difference between people who wanna drive economically and safely and those who want to put the pedal to the floor is just too big. It may have worked in the 50's to the 80's where fast cars were the exception, but nowadays virtuall every family sedan is capable of reaching 180 km/h or more. If you're going a leisurely 100-120 and someone is doing a low level flight at at least double your speed, things get dangerous. Traffic density simply doesn't allow that idiocy anymore.