Comment by Nifty3929

Profit is the best way to measure that economic outputs exceed economic inputs, which is the whole point. But profit doesn't work so well as a measure when the outputs are hard to measure per individual beneficiary. Inputs are generally always pretty clearly measurable, but outputs aren't always, as in the case of roads and bridges - although even there often you can.

Electricity is super-duper easy to measure the individual benefits of, so profit is a really simple and easy way to measure the overall effective economic benefit. It's not perfect though - there are external costs to consider which aren't paid for directly, but we have lots of experience with that across all sorts of industries and usually solve for that via taxes and regulation, which become part of the profit equation.