Selection bias. I don't doubt that the miners who are investing god knows how much is necessary to _require a contractor_ will have scaled enough to need to concern themselves with cost of electricity, but the _majority_ of miners are not going to be those people, surely?
Requiring a contractor isn't a big ask. All it takes is not knowing someone who has networking chops. I work regularly with around 10 mining operations, 8 of them explicitly relocated to get on hydro because of how inexpensive it is. These guys care deeply about getting the most kWh for their money, because they still have to deal with turning a profit, and anyone who doesn't understand that has not actually dealt with real Bitcoin mining operations.
Selection bias. I don't doubt that the miners who are investing god knows how much is necessary to _require a contractor_ will have scaled enough to need to concern themselves with cost of electricity, but the _majority_ of miners are not going to be those people, surely?