As speed increases, the chances of causing an accident increases. If you want to have fun, go on a track day or buy some private land. The public road, which is maintained for everyone's benefit, is not there to be enjoyed for fun (though it often can be completely legally within the speed limit) and breaking the rules which we agree with in order to continue using it isn't big or clever.
Do you have proof for that, because I doubt it. I think the chance of an accident is mainly by some far worse offenses like cutting someone up, not giving right of way, etc...
I'm not even on about just the fun factor, I'm in favor of increasing mobility and hate anything that reduces it. If I had to stick to UK or Dutch speed limits on the autobahn I'd lose up to 2 hours of time when I go to my family.
The entire point of speed limits enforced by fines, is to "encourage" people to not drive at reckless speeds. Yes the limit is entirely arbitrary, but it is what it is. It's entirely aimed at risk reduction.
The alternative is that we don't have a limit and people are only punished once they kill or maim someone through reckless speed, and with subsequent higher levels of road deaths, people in prison etc.
The alternative is far more fair imho. But people aren't killed through reckless speeds, they are killed by a disregard of other rules or failing to control the car.