that's where one will be anyway after some 100 hours, if one sets ones mind to it .
Agreed, but the vast majority of PPLs don't ever make it to 100hrs.
Another statistic I read somewhere, purporting to come from the CAA, was that some 90% give up before reaching 100hrs TT. That is only ~ 40hrs post-PPL.
This has been debated here many times but IMHO the inadequate amount of instruction is the main factor responsible for most PPLs chucking it in. Admittedly a large % were never going to stay anyway (the xmas PPL gift students, those doing it as a personal challenge, those who need to save for a month for each lesson, etc) but that still leaves maybe half who might have done, had they not felt like they are standing at the edge of an abyss when holding their new piece of paper.
To keep flying post-PPL, one needs a bit of a kick. Pre-PPL, the kick is the fact that you are not finished yet. Once you have the piece of paper, the old incentive is gone and
may be replaced with some new one, which could be going places, or changing over to an aerobatic course. Going places is why I learnt to fly, but it does require a bit of a budget, a bit of time, and access to something reasonable.
I had my fair share of crap instructors but in retrospect that never held me back - knowing the constraints of the training system and the WW1 syllabus.
My 1st ever instructor told me he had only 150hrs, but he was very good. Some dreadful ones had thousands. Perhaps the best were the retired ATPs.