The way I would put this is that I would expect a system with competitive generators and retailers mediated by a well run "free" market to more accurately discover the "natural" price for electricity than a public committee unilaterally setting the prices.

But those more efficiently discovered "natural" prices may be higher or lower than the prices previously chosen by the public committee. It's possible that the committee was setting artificially low prices subsidized by the public purse, and it's possible they were setting them higher than necessary. Either way, it could just be an accident - that they tried as hard and in as good faith as possible to pick the right prices, but just didn't have all the information or didn't model it exactly right - or it could be that they were responding to political pressure, choosing low subsidized prices because it's popular with voters, or choosing high prices because it's popular with lobbyists from utilities.

Markets certainly come with their own trade offs, and they certainly don't do price discovery perfectly either, but where they do have the advantage (in my view) is in spreading out the information-gathering, modeling, and incentive-following responsibilities across all the market participants, rather than concentrating them in a public committee that is inevitably a small group.

But this is really just the generic age-old argument between central planning and market structures. I tend to find market structures more appealing because I can contribute my ideas and my work into them as an employee or entrepreneur, whereas I'll almost certainly never be a central planner. But it's not a panacea by any means. There is a good reason we keep penduluming between more centrally planned solutions and more market based solutions in different areas; there are real trade offs between them and it's never obvious what the right balance is.