Oh cmon...
I have a house with great insulation. Thick walls, triple-glazed windows. Yeah it takes more time to heat up, but a week into a heatwave, all that material in the walls is warm. When it heats up during the day, it's an absolute pain to cool down at night, even with ventilation (and that's assuming the outside air is cold enough to be of any use).
A cheaply built capitalist house would at least freaking cool down at night, or between heatwaves for that matter.