Some Homes Are Behind Times
Many older homes were built before electricity was available, and were wired later. And like them, some older homes that were wired as they were built had only enough wiring for lights and a few other appliances, because those were the only uses that were known at that time.
But people kept on living in these homes, and kept adding to the uses they made of electricity without adding to their wiring.
What has this meant? Well, if electricity were like cars and trucks, you could say that some people are trying to put turnpike traffic through a back-country dirt road!