Suppose a family used to invest $2,000 per month.
At a 10% annual return, investing $24,000 annually for ten years would produce roughly $420,000.
If higher living costs consume that $2,000, the family does not merely lose $24,000 each year.
It loses the portfolio that money would have built.
That is why the damage feels larger than CPI.
The family is losing two things:
Current purchasing power.
Future ownership.