The only way to improve pricing is to have greater competition between the suppliers, and also to make it more easy and simple to switch suppliers, Many people already do look around and switch suppliers, but there is still a resistance/reluctance to change which needs to be overcome.
Which is all well and good for those able to switch. There are 2.3m families in fuel poverty who are unable to because they have had to switch to 'pay as you go' after being unable to keep up with the bills and now have to VERY slowly pay back their debt. The suppliers can charge these people whatever they like because they can't move. Therefore the poorest people are the ones that pay the most.