Houses rarely need AC - we usually only get a few hot days in a row, with time for houses to cool down in between hot periods. It is also usually possible to get airflow through a house, and cool things down enough.

Different story for badly built apartments, though. We used to live in a 1950s apartment, top floor with a flat roof. It reached 38C inside, when outside was 36C, and then wouldn't cool down at all during the night. It was unbearable, and we moved out!