Excellent M61! Repetition is definitely one of the essentials missing in how flying is taught. Repetition enables the desired action to be established in muscle memory along with all the other sensory clues that always inform us that the aircraft is approaching stall/spin. This is exactly what Chuck implied when he said if a pilot doesn't know his AoA he shouldn't be flying.
One of the principles of learning is Primacy and Recency, which is based on human psychological studies that show that, under stress, a human being will usually respond according to either the first learned response, or the last, depending on which was learned most effectively. Obviously, if the exercise was repeated enough for all the various sensory perceptions to become ingrained in memory, that's the response they'll use under stress.
Considering the above, if stall training exposes the student to those sensory perceptions very briefly - either because the instructor fears it, or that's how they were taught - then they won't develop a recognition for the combination of stick position and stick pressure, wind noise, slight sink felt in the seat of the pants, and engine noise, that together let a pilot KNOW AoA is close to stall.
Therefore, repeated prolonged exposure to pre-stall conditions is essential to enable a pilot to instinctively know when it's approaching stall. Then, they need repeated practice at controlling power and attitude at or below stall speed, so the aircraft can still be flown under his control. By ensuring the student gains confidence in maintaining control of the aircraft even in the stall, the pilot's basic need for security is satisfied, enabling them to pursue higher needs as listed in Maslow's Hierarchy of Needs. If this step is missing, that need will remain unsatisfied, preventing their progress up the pyramid. When understood fully, this explains a lot.