No, the energy required is a function of the price, not the other way around.

The bitcoin network adjusts the block difficulty (effectively the energy required to mine 1 BTC) every 2016 blocks such that the rate of creating blocks is fixed at one block (currently 12.5 BTC) every ten minutes.

If the dollar value of energy required to mine 1 BTC is significantly less than the current dollar value of a bitcoin then it is likely more hash power will be added to the network by the bitcoin farms, further increasing the network's hash rate, and as a consequence the block difficulty and therefore the price of the energy required to mine 1 BTC.

The price of energy required to mine a bitcoin follows the bitcoin price not the other way around.

This is just the discredited labor theory of value, applied to machines instead of humans.

In other words, I could spend an hour exerting effort and have nothing of value to show for it at the end?

That's obvious... You can work for a year and still get nothing... Because your work has no value in and of itself.

In general things are only as valuable as the "market" is willing to pay for them.

> That's obvious

Sure, I was agreeing / checking my understanding was correct :)

This will end very soon since 80% of coins have been mined already. So the energy consumption will only be miners processing transactions.

In my book, 2140 isn't "very soon" (based on the current Bitcoin mining algos).

The last 1% of unmined Bitcoin will last over 100 years. A majority of mining profits at that point will be from tx fees.

Sure, but "only" !== "majority".