Bitcoin mining costs a lot of electricity , time and cost of machines. But the reward is getting less and less. In recent years the exploitation cost has increased significantly . If bitcoin prices continue to decline , this can prevent many people mine bitcoin
I used to think that too.
Then i realised the whales don't care about mining cost. They aren't miners, they are whales, and all they care is that this BTC is something that they can manipulate and make a killing.
So, why would they care? You don't mine? Someone else would.
