IO540,
Yes, and we're getting into the whole area of the aging UK GA fleet, and its presentation to the consumer, I guess.
My experience, and I readily admit it is not long enough nor broad enough to admit of generalization, is that many people post PPL, who I guess may be candidates for attrition, would continue to hire from the school or club at which they learnt. That way there would, surely, be some advantage to the school?
Additionally, if encouraged to enjoy their flying, and not to allow it to lapse, they may well be encouraged to take further training.
Anyway, these are just options, as you say, the ideal is for recent PPLs to be encouraged to enjoy their flying and to continue to learn.