a low hour CPL FI 200hrs TT is a professional pilot and having demonstrated to the authority that they are such a professional they have no excuse for doing and therefore likely teaching the student anything other than that same standard. Where as even a 3000hr PPL is still a PPL.
One cannot possibly make such a statement. You might have a very diligent 200hr CPL student (after all, he won't be a working pilot at that stage), or a really stupid one (and I flew with a few of those) who is still thumbing through the airline job ads 10 years later, and you might have a really sloppy 1000hr PPL (let's not use the outrageous "3000hrs" figure which is 100hrs/year for 30 years) who sticks the key in and flies off (and probably doesn't fly far, over a 30 year period), or a diligent 1000hr PPL who takes a lot of care (and probably goes places, which the vast majority of CPLs never will, in any GA context).
I do not agree that CAS incursions are anything other than poor instruction and weak technique.
I don't think it is as simple, either. In a military setup you can say "blame the officers, not the soldiers" but not in a civilian setup where there is no selection and no underperformance sanction (other than in/ability to pay for the next lesson). There are numerous detailed reasons for CAS busts. I did one by chatting to a passenger and forgetting to do the planned descent at the waypoint. That was daft, and I learnt a lesson there. But the fundamental reason - the one which one cannot do much about - is people simply getting lost because they cannot navigate reliably using DR. Given the lack of selection for ability, etc, that one has to be down to the training and the syllabus, and avoidance of technology appropriate to today's airspace complexity.
Not suggesting that anything can be done about any of this from the regulatory end. Introducing GPS into PPL training would force mandatory installation which would be fiercely resisted by the industry, and you still have the variation in user interfaces, etc. It will never happen.
It will instead be sorted from the practical end: given time (another 20 years, in the UK) most of the fleet will be glass cockpits, and sticking a huge post-it pad over these is not viable. The FAA has done a master stroke (probably inadvertent) by requiring a checkride candidate to demonstrate competence on all installed equipment (to the extent applicable to the test so e.g. no need to program a G1000 for a GPS approach on a VFR checkride) and this indirectly forces the introduction of GPS in the ground school.