As I explained 5 comments up this thread, people are going to stop picking those "better" options because they're no longer economical. I think you just didn't notice that part of my argument, because you never responded to it.

Also, I don't think it's accurate to describe electrical resistance heating as "the thermodynamically worst heating technology possible". Electrical resistance heating is generally close to 100% efficient. It's actually thermodynamically possible to make heaters that are less than 100% efficient; MacKay explains, for example, that he heats his house with a 90%-efficient condensing boiler, and it's common for fireplaces to be around 20% efficient, because most of the heat goes up the chimney instead of heating your house.

Fireplaces are actually thermodynamically possible machines. I understand that you've never seen one, but I assure you that they do exist.

I've actually lived in houses where the fireplace had negative efficiency at times, sucking more heat out of the house (in the form of warm air) than they added back in the form of radiation.

That only makes sense in a situation where renewables have already more than taken over, which kind of makes the point moot. I'll concede your point that traditional fireplaces are even worse than resistive heating, though not that a gas condensing boiler is because you're not getting 90% of the energy in the gas out as electricity.