Disease is not a very good description, but basically what happens is that somebody does some work, say child care, which does not scale. They are paid x dollar

Disease is not a very good description, but basically what happens is that somebody does some work, say child care, which does not scale. They are paid x dollars for this service. Then the job market changes and they can go and get a better job somewhere else, so you now have to pay them x+y dollars for child care. Child care has not become more productive, the cost of living has not changed, but your child care is now more expensive. You could call that a rising boat that lifts all boats, but if you need child care it doesn't.