When you have a "natural monopoly" the thing you want to do is keep it as narrow as conceivably possible, i.e. the opposite of extending the monopoly on wires into authority over generation.
Moreover, the concept of a "natural monopoly" is painted across far more things than it actually applies to.
For example, suppose around half of the people on your street have a solar+battery system and the only reason any of you need a grid connection at all is in case it's cloudy for too many days in a row. Instead of you all paying a central power utility a lot of money, would it be economically feasible (in the absence of adversarial regulations) to run a second set of distribution lines down the existing utility poles or conduits and then install a single large generator that can take care of everyone on your street on those couple of days? Yeah, it pretty well would, and even if you didn't actually do it, the availability of that option would put competitive pressure on the incumbent. So they predictably work to make that economically infeasible through regulatory barriers using fraudulent "natural monopoly" arguments. You don't need an interstate power grid so that a dozen neighbors can share a backup generator.
And if something isn't actually feasible then you don't need to pass a law to ban it, right?
Even if you have a licensed electrician to do the work, they still make it an enormous ordeal to install new wires on utility poles. Case in point, what would it take for you to be able to install new fiber? There is no electricity even involved there.