A large part of the expenses incurred by the miners can be attributed to the capital costs. Setting up a mining farm can be very expensive, with all those mining rigs and air conditioners. Right now, there are only a few manufacturers that produce the mining rigs. And they don't have the spare capacity to increase the production 100x.
Not immediately of course.
But when gear that was sold for 400$ a few months ago can earn 720$ a month even at 10 cents per kwh every bitcoin mining chip maker will be able to go to TMSC and make them an offer that would take 1st place in the queue.
Abut air conditioning..common, we have stocks for that for tens millions of homes and businesses it won't be a problem to a few thousands small farms or a few hundred huge ones.
And I wasn't talking about 100x, but the price reaching 100k.
Not only the energy is not free, but in most places, you can even sell that energy so it's not like you get it for free and you have no use for it. Even if you use it to mine and generate profit you must first check and subtract what profit you would have had if you would have sold the energy directly to the grid without the headaches of monitoring bot miners and bitcoin price.