Disagree FC. Gipson capped out at the end of his 22nd year. He is barely training anymore and he is Perennial Allstar. Superfly Guy is right. Also you need to think that there is a difference between established teams like ours and newer managers. They often don't have the money to spend on PRIME trainees so spending 1/4 of the price on 1/2 the player makes a tremendous amount of sense for them.
The best strategy for newer teams, in my opinion, is train for a year or two, sell, buy new trainees. It doesn't work well to train for 4-5 years before making a trade because they often have so many other holes.