Sense of speed is... ::snip::
.
Umm, not true. Even @ 80 to 90mph GT6 doesn't simulate speed visually correctly. As speed increases, the eye does something naturally to compensate. It narrow's to increase vision on the most "constant" (slowest changing point of reference) and the least constant decreases in focus all the more greatly.
This phenomena is known as tunnel vision and happens instinctively with humans and animals alike. However at any point in time, the full scale of vision and focus is available in Gran Turismo, which to me is much less realistic than the effect of speed many of the arcade games you speak of attempt to recreate, albeit rather exaggeratedly. It's better than none at all.
Now obviously, objects within your vehicles range of speed will remain in focus, and things like braking, approaching apexes, and the like would and should greatly effect the changes in the sense of speed. And it should attempt to be as realistic as possible. But as it stands, Gran Turismo has yet to realistically simulate the sense of speed visually. And that is a fact. Not an opinion. Sorry.
the least constant decreases in focus all the more greatly
That may be partly correct but there are many other factors especially if pushing things.
I would assume adrenalin kicks in or some other mechanism when your brain decides this is quick you had better pay attention.
It has struck me several times just how clearly you can see the road surface at high speeds, because your brain has probably decided its important & you should concentrate.
That is totally contradictory to
The key is to (this is gonna sound crazy...) focus on your peripheral. It's an odd thing to do, especially while you're driving. The best thing to do is to be a passenger in the front of a car, or stand in the first car at front of a train, and just focus down the road/track. It won't happen immediately, but as you focus more and more, and your eyes start to adjust, you will notice it. It happens so naturally, it's something that's very easy to miss.
Obviously, if you focus on the road surface, which will take your eyes off the road ahead and place your focus directly at the ground, of course you will see the road surface clearly. But a TV screen is different, and it's easy to focus on the whole screen as one object, instead of interacting with it as if you are within a 3-dimensional space. So until we get Morphius, and maybe even after, motion blur will be all the more necessary.
I think what the OP and @SZRT Ice want is the sense of speed that GT6 gives you - in replays.
Play one back and leave it on the default (tracking) camera and eventually (usually on the longer straights) the camera will pan around and follow the car. The car remains in focus but the blurring of the surrounding scenery greatly enhances the sense of speed. I know replays at Madrid are good for this - other tracks may also do it.
So GT6 does do it - but not necessarily where the OP wants it.