In the UK, we have a similar system, and for a decent time it actually did deliver low energy prices for us. The way this worked was that a new energy provider could easily set up and offer low tariffs, backed by private investment and a gamble that long-term prices would stay low. Of course, when prices rose, that gamble failed... and who picked up the bill? Why, the taxpayer, of course! [1]
The overall effect of this game was that more astute consumers, who tended to switch to the lower-cost providers, were ultimately subsidised by the less-astute consumers who stuck with the traditional players. Or to put it another way, the rich were subsidised by the poor.
> Or to put it another way, the rich were subsidised by the poor.
I agree with most of what you've said but I don't agree that this conclusion follows. If anything when I was less well off I was far more inclined to put up with the hassle of changing providers every few months to minimise the costs than I am now.
I do think there were some efficiencies generated, it's just hard to figure out if a nationalised entity would have gotten there eventually. The online only account management for example probably saves a bunch over call centre staff and sending people around to read the meter.
The overall effect of this game was that more astute consumers, who tended to switch to the lower-cost providers, were ultimately subsidised by the less-astute consumers who stuck with the traditional players. Or to put it another way, the rich were subsidised by the poor.
[1] https://www.bbc.co.uk/news/business-63805028