The point is that he can't go anywhere to do that, so he'll do something else, and from an earlier age. This isn't about Sully, the individual.
Many potential pilots won't enter the industry at all for that very reason.
That's essentially the crux of the testimony. Those people who would get themselves trained with a large financial investment that will never pay off won't be able to justify it. Those who were military officers in the U.S. who have other university education and training (a very large proportion) will pursue those other paths. More than once I've seen a 45-year old F/O on a regional in the right seat, and I know that guy is pulling down $18K per annum.