Good question
Here's my take.
Ajax were a genuine european power only during the times of
Cryuff and
Rinus Michels, the legendary coach who invented
Total Football. After that, apart from the CL win in '95, they were a fading continental power.
Now they're in a position similar to South American clubs - producing precocious players, having them till they are established and then selling them for a fortune. I think Ajax, like South American clubs, are resigned to the fact that they can never dream of matching the moneypower of the top teams from England, Italy and Spain.
So they've decided to live off them, nurturing talent and selling them for a forune, and using that money to plan for the short-term future, at the end of which they'll have another precocious talent. Its a vicious cycle.
It'll take a truly great coach to reverse this trend - at least temporarily. If they win the CL (the UEFA cup is no good) and make the semis twice or thrice in the next five years, the money generated will go a long way in preserving the talent within the club, and what's more, get quality players to further imrove the side.