This way of looking at Nibbana, I got from listening to Ajahn Brahm speak. He made the point that the Buddha wouldn’t have used difficult, complex language when speaking to his audiences. He would’ve used local language that they could easily understand. (Indeed in the EBTs there are references to this, and the Sangha is told to use the local language when teaching the Dhamma. In practice, this means using the local idioms, the local slang even. Whatever makes it easier for people to “get it”.)
The Buddha moved within an agrarian society, going from village to village, with no electricity, but with the use of oil lamps, perhaps candles, and fires. As Ajahn Brahm says, the people would understand easily when they were told about “putting it out” or “extinguishment” or “cooling completely”.