People still do not understand how gas and electric billing firms work in the UK

People still do not understand how gas and electric billing firms work in the UK. Basically who you sign up to is a billing firm. They charge you what your gas or electricity is plus the costs they have. They do not supply your gas or electricity. That is a different firm. As such if you made the switch you save money. They keep costs down often by only having a few staff or these days do everything online. They are not responsible for the gas or electricity costs. To put simply if a unit of gas or electricity costs £1 then the cost to you is £1 plus what it costs to run the billing firm. A few firms went bust presumably because they fixed costs to customers then the gas and or electricity costs went sky high and they were charging customers less than what they were being charged. And so went bust.