I can give you my thoughts after many years of wondering myself.
First, if you are going to build a car that can go faster, you have to engineer it to do so. That equates to additional costs and beefing up the parts of the car that will fail when used under those conditions.
Case in point…. my last stint at the Daytona Speedway under high load and continuous runs hitting the speed limiter caused my CVs to overheat and eventually fail. There are not that many tracks in the country where you can operate the car under these conditions. Also, there are not a lot of people who would operate the car and drive it to the point where these failures would be exposed.
So, my takeaway is that why build a track car to go faster than most tracks can support? Again, why build and engineer a car that only a very small percent of people will ever realize that kind of performance? If you build it to go faster, you will have to engineer it to handle that. The car is already a pig as it is and you are probably going to have to add some expensive weight reduction or make the car heavier by beefing up the drivetrain components.
I can say that the two half shafts that i had to replace weighed about 70 pounds. Want to make the car go faster, those shafts and much of the drivetrain would have to be substantially more robust.