If you have ever been to a race track when they have an open track day you would have noticed that the officials will seperate the drivers into groups depending on ability of the car and/or driver. When a driver is seen to be going too slow or too fast for the group they are in, they will be pulled from the track and put down or up a group. This is done mainly for safety reasons, as the slower driver could easily be hit by one of the faster drivers. In other words, it's done so that the faster drivers can go fast SAFELY.
It's not hard to understand that more skill and/or a better car will allow you to go faster without crashing, which is why there is a variation in speeds for the different groups.
If the officials decided to put all the cars on the track at the same time and all the drivers wanted to drive at the speed they were able to safely drive at, there would be carnage as the faster drivers tried to avoid the slower ones. It wouldn't take too long for one of the faster cars hit a slower car and a crash would happen.
Now, if you told all the drivers they had to drive at a speed that was roughloy average for what the cars were capable of, the less experinced drivers would soon wind up in the kitty litter, or in a tyre wall. This would simply be unavoidable as some of the cars (even with more experienced drivers) just wouldn't be able to handle the high speeds required to keep up.
The alternative would be to pick a safe speed that everyone could handle. The really experience drivers would almost never crash, and the inexperienced ones would have a much better chance of staying on the track. Not much fun for the better drivers though!
So the difference between a race track and the open road, is that variation in driver or car ability is almost completely eliminated on a race track, but on the open road, drivers and cars of various ability are on the road at the same time, and it is unavoidable.
Speed limits as they are will never prevent all the accidents, and even reducing the limits probably wouldn't help much either. But increasing them, and certainly exceeding them, can (and does) only make it worse.
Shurely even those of you who advocate for higher speed limits can understand that?