I agree to the fact that there's only 1 fastest line (entry, coner, exit speed) for a particular car.
When tires are fresh, track grip level is good, it is relatively easy for a driver to steer the car along that line. However, as the race goes on, wind direction, tire / track grip varies, following that ideal like becomes much harder and this is where drivers' style in brake, steering and throttle modulation comes into play. Also, don't forget the brake balance and many other adjustments the driver plays wtih during the race.
I don't agree that drivers back in the days are more skillful, I just think that their skill sets shifts into different areas as technology progresses over time.
__________________
|