>> It'd be much more sensible to deregulate and let the people who profit build the interconnects.
Firstly, it's worth saying that in markets with high barrier-to-entry costs, it's not easy for the "market" to protect against profiteering.
Or put another way, if the local utility decides to charge more, its not like you can just build a power station, and connect to the grid, to undercut and take a profit.
Equally, given the cost of starting up, concessions are made to protect monopolies (or semi monopolies) to avoid unnecessary duplication of infrastructure.
Regulations though can be good, or bad, depending on your point of view. They either work for the business (keeping out competition) or for the consumer (preventing price gouging.)
And it's not just today's profits that matter but tomorrow's as well. If I'm allowed to charge more during periods of high demand, that encourages me to increase scarcity. I'm incentived to provide less power, and get more profit.
So deregulation likely ends badly for the consumer. It likely leads to scarcity since that improves profits. On the other hand deregulation has allowed me to have residential solar, dropping my energy bill by 80%. And high prices make that financially attractive. So some deregulation good?
My point is that the balance between regulator, provider and consumer is a very fine one, and messing with that balance can have consequences.