With IO540's position, one has to remember some very important things-
They fly with GPS under BRNAV in controlled airspace with ATC service.
If the GPS fails they are entitled to radar vectors or there is guaranteed to be appropriate along track navigation aids which can be tracked.
If the Navbox has put out some weird heading or for whatever reason the GPS does not take them the right way, ATC will notice and will offer assistance.
Now look at he average PPL with or without GPS. Who is going to notice for them that they are unknowingly about to leave Class G airspace due to an error and who is going to steer them in the right direction if they rely on GPS and it fails?
They are two different operations entirely and it is like comparing how much BA pilots are aware of the variation where they are to the PPL below the airway at the same place ploughing on with at best a FIS from somewhere.
People who can not navigate should get IR's to fly the airways always and an oxygen system so that one never has to drop out of the base on long flights and then they don't have to worry because if they can't find their way there will always be ATC to help.
They are the ones who could be described as the lowest common denominator - the strugglers, those that simply will never more than plodders. Should they be chopped at the Nav stage?
That is the point - unless one operates a training system that weeds out those below a certain standard at various stages one will have no choice but to cope with the person with 500 hours and who can't navigate without a GPS.
Regards,
DFC