$60 (or, more currently, ~$83) is the block reward, at the current price, divided by the average number of transactions per block. It does not even include the added incentives from fees.
The value you try to compute is currently exactly $79, including fees (which are about $1). If the number of transactions were to double (or halve) tomorrow, that value would halve (or double). You are just dividing fixed ongoing rewards by a variable metric unrelated to the rewards (transactions). You are propagating a misconception that somehow this represents the cost of a transaction.
Yes, and the block reward can be claimed without any transactions in the block.
On BTC this never happens, on other chains it's quite common, since no one uses them.
That $60 in electricity 'per transaction' is simply not correct, the value of the block reward doesn't come from transactions. The transaction fee does.
