It's absolutely not an absurd set of assumptions. The majority of the demographics you're worried about are beneath the replacement rate. They are going to necessarily reach a point where the youth workforce cannot sustain the outsized elderly population or protect them in a war scenario.
If you do not want to defend Europe's front lines with teenage conscripts and geriatric riflemen, you need a way to bring warm bodies into the fold. Refusing lawful immigration will undermine domestic security, doom the elderly and ruin pension funds for future retirees. No sovereign wealth fund is worth losing your sovereignty over.
If you do not want to defend Europe's front lines with teenage conscripts and geriatric riflemen, you need a way to bring warm bodies into the fold. Refusing lawful immigration will undermine domestic security, doom the elderly and ruin pension funds for future retirees. No sovereign wealth fund is worth losing your sovereignty over.