Nobody is saying that PoW doesn't exist, so no, I'm not going to read Bitcoin's source code. That is such an odd thing to say.
You can calculate cost per transaction because each block has a maximum number of transactions, irregardless of the current PoW difficulty. I don't know why you're so fixated on this. You can take 10 minutes of electricity costs and project it onto the number of transactions in the last block.
You can calculate cost per transaction because each block has a maximum number of transactions, irregardless of the current PoW difficulty. I don't know why you're so fixated on this. You can take 10 minutes of electricity costs and project it onto the number of transactions in the last block.