• the network is self-adjusting. if hash power begins to decrease, the network will decrease difficulty to maintain the target of 10 minute block times. lots of things could lead to decreased hash power. the whole network could be run with a cleverly configured raspberry pi

    • the whole network could be run with a cleverly configured raspberry pi

      Which would defeat the entire purpose of a distributed blockchain. I’m ribbing you, of course, on that ;-) Bitcoin was not built for efficiency and the very basis of distributed proof of work trades efficiency for security. The more “successful” it gets, the larger the incentive to waste power in a fight to win each block reward becomes - by design.