This does not work at scale. Sure, there is plenty of anecdotes how you can successfully play this game as a consumer living in a rural house with electric car, power wall, and rooftop solar, but try to telling about it to someone living in a high-rise apartment or to a heavy industry business. Your preaching will fall on deaf ears.

IIRC there are several utilities in the UK which provide option to price electricity dynamically, but they are not popular because people do not want to play this game. They want reliable supply of electricity for reasonable prices. Trying to mold consumption to satisfy intermittency of generation is nothing more than shifting the externality akin to telling people "you must plant trees to offset CO2 emissions!".

3.3 million households in England were on Economy 7 tariffs in 2021 - around 14% of households

The most popular UK electricity retailer is Octopus Energy which is specifically focused on variable prices and flexible consumer demand. By what metric do you mean variable rate retailers are not popular?