Michael – I think one thing you need to consider are the forces in the static vs. the on-track situation.
With the kart sitting still on the ground, no matter how much caster, ackerman, etc. you have, when you turn the wheels, it won’t roll as freely as it will in a straight line. I think the only point the “books / setup documents” are saying is that a kart naturally wants to drive straight ahead.
Yes, if you take a lot of the geometry out of the front end, it will roll “easier” under no load with the wheels turned than with lots of geometry (apply a simulated load and results may change)… but still not as easily as with the wheels pointed straight ahead… the kart naturally wants to move in a straight line… push it with the wheels turned, and the wheels will straighten themselves out very quickly!
What this little demonstration isn’t doing is telling you about the impact of adjusting caster, ackerman, toe, front track width – those things really come into play when a kart is moving. That’s where the points that TJ and Larry, etc. are making become relevant.
As to where does the “freeness” of the kart derive from? I’d say it’s a balance between a LOT of factors… part of it is the front end, part is the rear, part is the overall balance / seat placement, part of it is grip levels – in the track, the tires, the frame, etc.
Yes, you want to lift the inside rear… but (a) there are many ways to do it… and (b) some will make you faster, while some will make you slower.