[wldlyinaccurate]

If you think the presence of a power grid is the same as having power 24/7, you need to spend some time in other parts of the world. In some places you are lucky to have power for 12 hours a day.

You're looking at this from a position of privilege. When I say "cost is another reason", what I'm really saying is that many people literally can't afford the electricity or the electric heater itself. The vast majority of the world's population earn no more than a few US dollars a day. They are saving for their next meal and hoping they can afford to have their shoes repaired soon. They aren't in a position to consider how they can be more environmentally friendly. They just want to survive.