If BTC were to go to $500,000 in this era it would cause a catastrophic mining bubble:
$500,000 x 25 = $12,500,000 per block = $75,000,000 per hour
$75 million per hour would drive the mining to attempt to use 675 GW. This is about 30% of all the power generated on the planet.
So $500k price will not happen now. It could happen in 13 years, when the block reward is 1/16 of 25 bitcoin/block. The electricity cost of mining bitcoin is less than 2% of world electricity cost. The electricity is even lower if you include the building, salary and management cost.
We also need to include the cost saving by removing some of the present banking service.