Your point is good, but unfortunately I can't see a 172 or Cherokee being terribly useful either? With a 100-105 kt cruise, you generally don't beat the car by a significant margin when you think of flight planning, preflight etc. My cutoff is ~150-160 knots for a cross country machine.
Things an aircraft needs to be for me;
1. Small and completely maneuverable for sport flying and short cross countries.
or
2. Fast and able to carry 4 real people and bags IFR for a true cross country.
or
3. Historical significance or nostalgia. (Cub, Stearman, etc)
I understand the need for a GA trainer, but I do think people are missing out on some of the joys of flying if they never move past a 172 or Warrior. It doesn't need to mean more expensive either. A Citabria fits the bill for me.
My ideal aircraft is a fast, two seat, aerobatic, cross country equipped machine. Currently that is most economically filled by an RV.
Fly a cub around at 200' with the door open, sometime, or do a slow, lazy barrel roll in a Citabria. It'll change your life ;-)