Have you watched any of the Martin Lewis or current (sic) affair programmes discussing this issue?
The price cap has increased because it is based on a running 6 month average wholesale price, and gas price has been progressively increasing (and as Culzean says, between 45 and 50% of our UK electricity comes from burning gas). It has sky rocketed in the last month, and unless some staggering decrease comes in the next couple of months (extremely unlikely) then the next review in April 22 will result in another increase of probably at least 30% (maybe a lot more??).
No energy retailer will now offer any fixed price deal less than the expected or projected price in 2022, which will be a huge increase over what we've had in the last 12 months. The lowest prices you can get right now are the price-capped standard variable tariffs. Those prices will (should) last until April, but will then increase dramatically.
All the cheapo "suppliers" aren't suppliers, they are simply entrepreneurs, marketing agencies, they buy from A and sell to B. Unfortunately the price they are allowed to sell at (to B) is now capped at a lower value than they can buy from A, so they cannot survive. It was a business model built on sand, fine until the tide came in and washed the sand away.
The potential disaster comes when the big companies who inherit the bad deal customers from the failed businesses can no longer accommodate the inevitable losses which come from having to buy more energy than they had hedged for at the hugely inflated prices but are only allowed to charge the capped amount. The models were not based on widespread cheap business supplier failure. Then the big ones go to the govt and say we can no longer support this, what are you going to do about it?