Being a successful combat pilot is a pretty fair metric of having above average flying skills. Learning to fly in a glider, where a new pilot learns feeling airflow and seat of the pants from the very beginning... helps build better than average hand flying skills. Like all that energy management stuff Contactflying talks about.
If I'm not mistaken, there is indeed a lot of energy management and trading off potential vs. kinetic energy, adding and reducing drag relative to turns and G forces, etc. involved in tactical air combat. Much much much more so in WW2 than today (they didn't have the thrust to overcome drag that we do today).
Although I'm not saying that having glider training was a guarantee of becoming a WW2 fighter ace, I don't think it's a stretch to say that those better basic hand-flying and energy management skills played some part in the results. We can agree to disagree on that point with no hard feelings or ruffled feathers.
As far as the general concept of getting younger people interested (whether in pursuit of flying for fun or flying for a career) with all respects to the people who have been in the flight training business... the way it has been done for the last 50 years is clearly not working now. Otherwise we would not be in the frightening decline that we're in now. Among the percentage fo the population that is interested in learning how to fly, I'm almost certain that the most significant barrier from their perspective as potential students is cost. So if there was a less expensive way for them to become pilots, there would be some increase in the number of new student starts.
(For goodness sakes, for those of us who are already pilots, and have given up heart, soul, mind and mental health for most of our lives as hopeless addicts... the cost of flying is what's keeping us from flying as much as we want to. And we're already hooked.)
As for the problem of getting people interested, that's a separate problem. Whether it's the attention span issue, or the competition from computer games, or poor outreach and advertising - we can discuss that all day long and come up with a wide range of problems and solutions.
To address the growing and future need for new professional pilots, once again the issue is cost. Back when being an airline captain was considered a lucrative and high-paying job, you could make a case for going into debt for an expensive professional pilot education. Nowdays, airline pilots are making less than plumbers and welders. Yet the cost of getting X hours and Y ratings is far far higher than it ever was before. If anyone ever did become a career pilot because it paid well, those days are gone.
So a college graduate goes to his/her parents and says "I want to be a professional pilot, and it will cost $100K to go from zero to a heavy type rating and have enough hours to be seen as a serious candidate by an airline. Or I can spend a bunch of years flying freight, and starve while I'm getting those hours, but by then I'll be too old for them to want. By the way Mom, when I finally do get my first airline job I'll be starting at about the same money as the guy bagging the groceries at the market. But don't worry, after a few years I'll be making about the same money as Tattoo Tommy across the street with the 87 IQ makes welding on truck frames. Will you guys please put up your house so I can go do that?"
With the possible exception of flying cocaine in a stolen 421, I don't think any young American will be getting into flying because of the money any time soon.
Which leaves us back at the OP's original question about getting student starts up. Perhaps some of the neurosurgeons at AOPA and EAA have done a study or two to generate some data on what the actual and perceived barriers are from the potential new students' point of view. I'll bet that the cost is at the top of the list.

