For example 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.
After July, the bock reward is reduced to 12.5. So that will just be 15% of the world power generation. After a few more halving, it will be even lower.