Yes, of course you can generate your own electricity. But that also costs money. If I invest 150k today, I have low heating costs for 20 years. If I don't invest anything today, I heat for 20 years for e.g. 60k. Sounds strange, but that's how it is. I have nothing against heat pumps and well-insulated houses. But pretending that every grandma has to renovate her terraced house from the 70s tomorrow at a six-figure sum because otherwise she'll end up in debt is too short-sighted. You have to look at it individually. If grandma's gas burner breaks down right now, it can still make sense to have a new one installed. In new buildings, I would probably avoid that as of today.