People in Germany advocating an additional tax have either never worked, payed bills, are stupendously rich, just insane or don't have responsibilities towards others.
Sorry, there is a limit on how much you can use taxes and that limit is staunchly in the red because of naive promises made in the past.
I think the current little pupil rebellion is something very worth supporting. But their demands are naive.
Your proposition would be a more efficient mechanism.
Currently there is a discussion about giving people a fixed amount of money for the additional costs this tax would cause.
What a waste of time...