On the other hand, blockchain mining responds to more efficient hardware by increasing difficulty in order to compensate for the impact of improved hardware on the hash rate, while still doing the same amount of work (i.e. processing the same amount of transactions).
The comparison is absurd and intellectually dishonest.
Maybe the cumulative effect on energy spent for playing tetris, or minesweep (not to mention much modern videogames) is not so small after all.
... Equals huge amount of entertainment hours. What you don't seem to be grasping is that the power consumption only increases the minimum amount necessary to meet demand for entertainment hours, i.e. the more power consumed the more entertainment hours produced. With PoW, power consumption continually increases but the amount of transactions processed remains the same. PoW is clearly and inarguably inefficient by comparison.
If we except the tetris, or minesweeper...