The OP has answered his own question in the question. You have held a PPL for 16 years and I presume that during that time you have never unintentionally spinned?
Most aeroplanes are not cleared for spinning any more than a 747 is.....and you wouldn't expect 747 spin training to be carried out.
My view is that spin training is best left as part of an aerobatics course, post PPL, done in a proper aeroplane with a proper psycho (Aeros FI
) sat next to you. Also as far as a PPL candidate is concerned, then it is probably too much to take in to be really worthwhile.
Sure, FI's etc. should do spin training as they have a higher than average chance of getting chucked into a spin by a student but by the time you become an FI you have a good amount of experience.