but it's not like that
No, but that's exactly what would happen if your suggestion was a reality - it would be the logical conclusion.
But as it exists at the present the system relies heavily on a significant amount of people paying more than they should for their energy supply, without that caveat the system would collapse leaving only one energy supplier.
So you can't on the one hand claim that everybody should go for the cheapest supplier whilst on the other hand hope that not everyone goes with the cheapest supplier.
BTW I can't believe that you are comparing the car insurance market with an energy market dominated by six big energy companies.
A week ago SSE announced price rises more than 3 times the rate of inflation, simultaneously it was widely reported that it was expected this would trigger similar huge price rises from the other energy suppliers.
No one felt the need to explain precisely why the other energy suppliers would also increase their prices by a similar amount. Apparently just the fact that one has increased its prices is enough to justify others doing the same.
So there you have it, the "free market" in the utility/energy sector drives prices up, the very opposite of what we are told is suppose to happen.
im paying virtually the cheapest gas prices in Europe
You are not paying the cheapest gas prices in Europe, although you are paying the lowest taxes on gas in Europe. This is a direct reflection on government policy and has absolutely nothing to do with the energy companies.
And you would expect the UK to have some of the lowest gas prices in Europe, the UK is after all a significant producer of natural gas, ie, the UK is the 18th largest producer of natural gas in the world, how many other European countries compare with that ?
If you exclude the taxes, which has nothing to do with the energy companies, French domestic consumers pay approximately the same for their gas as British domestic consumers.
France ranks 68th in the world with regards to natural gas production, a far cry from being 18th.