There are pilots who know the POH off by heart, and pilots who know their aircraft. They are rarely one and the same. It won't change.
True but how many students are given the figures for approach and landing by their club and they turn out to be 5 or even more knots higher than the POH? (As tecnow has been given for his 152) First time they have a go at a short field after their license issue they're having a meet and greet with the upwind hedge. At least the POH gives you some info to work with, you can fine tune that to the aircraft you fly.