Not disagreeing with you, however.......
I would rather the PPL came out with a good knowledge of the fundamentals of flying in daytime VFR, coupled with a healthy understanding of his own limitations. Teaching GPS to people who can't navigate properly using DR and eyeball is not the answer.
The syllabus and the number of exams has grown since I did mine. Has it made for safer pilots? I don't think so.
People infringe for two reasons:-
1.They don't know that they shouldn't be where they are.
or
2. They don't know that they are where they are.
Arguments about GPS or for that matter any radio based navaid are irrelevent to the syllabus for basic daytime VFR IMHO.
There is a very good argument for post-PPL training. Irv Lee has a very good approach to it and the biennial flight with an instructor is also an ideal opportunity (once you evade the people who think it should include the LPC requirements).
The way is open for instructors and schools to run post-PPL navigation courses, including the use of GPS. I don't see them advertised, which is a pity as there seem to be many who would benefit.