The aging population will likely require ever-increasing spending on healthcare.
Literal
Aging population [topic-は], health-management [for-に] increasingly many expenditures [subject-が] necessary become [conjecture-だろう].
A formal statement about demographics. ~となるだろう combines ~となる (formal 'to become') with だろう (conjecture). ますます多く ('increasingly many') marks the proportional escalation. Written/analytical register typical of policy discussions.