Yeah, I drive a lot of cars in a lot of circumstances, including on tracks, for many years now. Without getting too deep into it, it's part of my job (no I'm not a pro racer, but I should be lol).
I don't get this lack of speed thing, either. I couldn't feel any more different about it. Going back to real life, once you're somewhat skilled and confident at track driving/racing, the newsflash is this: You don't really register speed unless you're driving something at the bleeding edge of high speed or in true high-speed corners. The speed itself doesn't even begin to register to me until well above 150 mph, at least not in modern cars. As a well-known IndyCar drive told me once when discussing this topic: Nah, you don't really consider the raw speed--until you lose the car and are spinning/crashing. As soon as he said it, I was like, yes that is absolutely true, I know what you mean LOL
Truly, though, raw MPH means far, far less and feels like far, far less in a track/racing environment than it does on a public road. Yeah, if you go nuts and decide to rock down your local highway or freeway at 140 mph (or even less), it feels crazy but that's at least as much to do with the mental context (fear of going to jail, what you're normally used to on the same road, etc.) as it is to do with the pure speed itself.