Seems you have never been to Germany ;-) No offense. Most highways have a speed limit only some have none.
And most of the highways that don't have a speed limit are quite narrow so while it is possible, no sane driver would do so.
If you look at highway A5 as an example. This highway has 8 lanes, which makes driving fast quite dull since you can not really feel the speed relative to the environment.
The figure I've seen is 50% of Autobahn is without speed limit, 25% with permanent limits (due to noise control, permanently high traffic volume or intersections) and 25% with temporary limits (depending on buildings works, weather, congestion). Of course the perception is probably worse because more people use the congested parts with speed limits, and due to the limits they spend more time on those parts...
And most of the highways that don't have a speed limit are quite narrow so while it is possible, no sane driver would do so.
If you look at highway A5 as an example. This highway has 8 lanes, which makes driving fast quite dull since you can not really feel the speed relative to the environment.