Right but it's not as simple as buying young players who need time to develop and letting them improve - they won't improve if they're not being coached right, and meanwhile the short-term results won't be as good as they can be if the players aren't deployed in a sensible system with cohesive game plan.
Buying young players and selling them for a profit has nothing to do wth the moneyball approach used by Billy Beane.
Beane signed David Justice, age has nothing to do with it. Resale value had nothing to do with it. He'd have signed a 50 year old with one leg if his OBP warranted it. The overvalue was to do with 'sexy' players like Damon, or closers who could have their numbers inflated if used correctly.
Heaton, Snodgrass, Elmo, Jedi, Chester, Albert, Kod are a few more.