Most of my experience has been in a autoX. It's been my experience that when I set-up the car to rotate for slower corners, the car suffers looseness in high speed transitions. In order to set-up the car for high-speed transitions, the car will feel tight and want to push in lower speed stuff.
I guess there are two differences in what we're talking about
: transitions are not steady state cornering and the high speed I'm used to in autoX is not top speed for the vehicle.
Maybe you're completely right most vehicles will have terminal steady state understeer but I argue most vehicles will also become more loose in transitions as speeds increase.
I also didn't take into account aerodynamic lift of the front...