Not just tax and elder care. If you have fewer young people than old then when those young people take the place of their older colleagues in their various prof

Not just tax and elder care. If you have fewer young people than old then when those young people take the place of their older colleagues in their various professions you wind up losing a lot of tacit knowledge. If there are 1.5 olds for every young then that young one needs to learn 150% of the skills and knowledge that they did before. In such cases the extra information often gets lost. This is how population collapse leads to civilizational collapse.