if you look below you can see difficulty has basically just gone up since the nov 2021 high go 69 k
My guess is that's because the hashrate per watt went up on newer miners. One way or another, if it wouldn't be worth the running cost, they'd pull the plug.
common sense would say you are correct but that chart shows more mining.
and the efficiency increase do not make up for the price.
ie 69k in nov 2021 with a 30 watts a th machine the diff was under 40t
and 60k in aug 2024 with an 17 watt machine the diff is over 85t