>It's not like "the price is fixed to the price of gas" is some iron law of nature.

It kind of is.

Gas is the only source of electricity currently which can be scaled up and down at will and on demand.

Even once grids eventually go 100% green we will probably still use (green, synthesised) stored gas as the power source of last resort on cold, windless nights after batteries and pumped storage have been depleted.