The Dutch trainer commented on the likely exit of three of his players in the near future, suggesting they were following in the footsteps of their earlier Oranje counterparts
The Eredivisie champions were content to sell on the likes of Rafael van der Vaart and Nigel de Jong at an early age in the past, and De Boer underlined that their moves have influenced the overall policy the club has adopted.
"Van der Vaart and [Nigel] De Jong began the trend of players leaving Ajax when they turn 22," the former defender told De Telegraaf. "The philosophy at Ajax is simply that the inflow of youth players is set higher.
"My stance towards Alderweireld and Eriksen is based on their contracts expiring this summer, even though I hope they will stay.
"If they leave, Siem will be the only player left of his generation. If boys like him stay until they are 24, then they would already have stayed an additional two years."
The attacker has developed into an important element of the Amsterdam outfit since he was promoted to the first-team in 2007, and was made captain in the wake of Jan Vertonghen's departure.
And Siem de Jong said he was not set on an exit from the club, adding: "They only asked me about my plans at the end of this season.
"I told them to consider any important opportunities elsewhere for me, but that does not necessarily mean I want to leave."