> Like, a new power pole costs (say) $1000 regardless of how many watts are going through the wires attached to it. Someone has to pay the person that cut down the tree and hauled it to its final location money.
That pole is carrying the power for, say, 100 people.
Half of them use a below-average amount of electricity. If you stick them with a $100/month fixed fee, they don't need a large solar/battery system to get off the grid entirely, so you've made that economical and that's what they do.
Now you have the same number of poles and half as many customers, so the fixed fee rises to $200/month, and more customers do the same thing. This is not going to a great place.
Meanwhile there is a rural road somewhere that only has two things on it. One is a large commercial operation and the other is somebody's house. Putting up poles along that road is going to cost $100,000, but the commercial operation is content to pay the entire amount because their alternative is buying land somewhere that it costs significantly more than $100,000 more. The house on the same road is not content to pay half of that and will just use their $50,000 to install a solar/battery system and have quite a bit left over, even though a model where they only pay for usage would get them to sign up, and the power company is installing the poles either way.
The problem we're looking at is that if you charge a fixed fee for a grid connection, low users opt out of the grid, and then the fixed fee goes up and creates a new set of low users. But if you charge for distribution per kWh, everybody installs local solar generation because it's cheaper than any generation method that has a significant distribution fee as part of the cost per kWh, which in turn raises the distribution component of the price per kWh even more. Under the first option, a large proportion of rural and suburban customers aren't going to want a grid connection at all. Under the second option, they'll take the grid connection but then only use it if local generation isn't available (i.e. it's cloudy) and the grid price per kWh at those times will be quite high. But that's plausibly the better of the two alternatives, because a grid connection with a high price per kWh will generally be better than losing power at those times, or having enough local storage/generation to prevent that from ever happening even in rare circumstances.
A third option is to charge everyone the fixed fee for the power grid and force them to take a grid connection even if that isn't economical, but that's even worse. You've essentially created a head tax with no way to avoid it even if you can't afford it, because you can't cancel your service and you can't pay less by reducing consumption.