The reason students drop out is:-
1. It's expensive.
2. It's very time consuming.
3. It's quite hard to learn to fly.
4. Many are not of a suitable psychological disposition (nervous)
5. They.find out how long it is going to take to get a licence , how severely restricted they are in the use of the aircraft for weather reasons , the discovery of the need for instrument training if any sort of utility is required, and the fact that they can't just go from A to B with their mates on a pre arranged date or when they feel like it at the drop of a hat.
The reason that licenced pilots drop out are all af the above, plus (especially in europe) massive over regulation.
Where the summit came up with all that modern idiom garbage for reasons I have no idea.