I would still insist that heating is the only way to make much of Europe permanently inhabitable. Yes, houses get more efficient and the energy necessary gets less (same is true for cooling a house though). Still, we had a week of permanent -10°C 1,5a ago. Without heating we’d probably have to count the deaths in the millions for that week alone.
I mean, there have been more than a dozen confirmed assassination attempts on Hitler (even suicide bomber attempts among them) and a few more unconfirmed possible attempts. The future did try their best (or just some brave people from the time itself).