This is already happening, but I don't know to what extent (especially over multiple countries), but we moved into our extremely well insulated house (thing 3 layers of glass) in the Netherlands mid 2020. Heating happens using a ground source + heat pump, cooling using just the ground source and passive pumping, ventilation is centralised and uses heat exchange.

During some 30/35+ waves of the last few summers we kept it below 23 degrees Celsius inside, even over many days of heat.