I don’t think it’s that suitable alternatives that could make a lot of headway into limiting the problem dont exist, it’s more that a lot of people are making a lot of money from the status quo and have a vested interest in ensuring the status quo remains. You can bet your bottom dollar that if those people had found a way to continue the gravy train with the alternatives then they would. Eventually they are going to have to consider that if society collapses due to their actions that the currency they are accumulating will be worthless without the societies that dictate its value. I don’t think that will happen until we start seeing some of the climate change chickens come home to roost. It’s going to be unpleasant for a lot of people and might be too late.
I assume it was only implemented under the provision that it doesn’t apply to MPs, Lords or any of their special pals.