> Your statement is entirely unclear. Could you restate it? For Steelman purposes, I'll ignore the non-sequitur about cheating.
By cheating I meant making a sidechain that would become longer than the mainchain, thus enabling a double spending attack. If the amount of money to be made in double spending attack is higher than honest mining someone will make it, the only thing protecting against that is that the cost of mining must be large enough compared to value being transferred.
>I'm not sure what you mean. In general, energy costs seem to be dropping over time
Back when it was CPU mined. Before even the first GPU mining. It was just about proving that you have an actual HW dedicated into the task.
Exactly as mentioned in the quote that you said. He didn't have a clue that it would become dedicated HW that has only a single function, burning energy to calculate SHA256 and nothing more.
Also do note that the whole concept of non mining node was foreign. Instead of the original design of nodes that mine we're in situation where nodes don't mine and most mining happens in centralized farms.