Because we don't design homes for self sufficiency. In cold areas, you could have most of the triple glazed windows facing south, double walls with insulation and thermal mass. It wouldn't freeze in winter, and heating could be optional. Or, you could burn some wood or use a small heat pump to keep it nice and hot.

We could also burrow underground. Or use straw bales.

The powers that be HATE us being independent. They use zoning laws and building permits to make innovation illegal - heck, they even outlaw clothes lines in some areas. They also hoard crown lands and won't allow you to stake a claim.

What they really want is renters, or home owners paying lots of tax to municipalities and governments - and with banks holding mortgages so that you are slaves forever.