Because air conditioners can't be relied on to keep everyone alive into the future.

The rich can use air conditioners for comfort, but poor people will need to learn that costs have risen to a level where the difference between comfort and survival isn't small enough to ignore. You can't just live out your whole life with extra wealth to spare for comforts like air conditioning while there are 8 billion of you. You have enough wealth to live for as long as you have enough wealth to live for, and you can meet your cooling needs for longer at the survival level with fridges / freezers / ice makers than the comfort level with air conditioning.