Does AI have a future?

With all the hoop-la about AI, I recently read an interesting fact: The "intelligence" of AI is generally proportional to the computing power put into it; and that relationship is logarithmic. I.E. initially you get results as you put more power in but that relationship tapers off. You must put in more and more power for fewer results.
Moreover, the consumption of energy is enormous. One recent plant envisioned by Mark Zuckerberg consumes more energy than all of Scotland. And mu;ch of that energy will come from coal!
Thus whether AI will truly be revolutionary without destroying the planet would seem to be dubious.
And of course, there may be other constraints on what it can do.