Basics of economics:
Economies are a form of an ecosystem, where elements in the economy must provide inputs into the system the system wants, and take outputs other parts of the system want. The value of the inputs and outputs must line up. One can implement government programs that address issues in the system, and increase value by fixing economic environment. Unless this is done, nothing happens.
Question: What exactly does enforcing a ban on gum do for the economy that would fix anything?
You could also ask why the government doesn't just dig a giant hole and keep filling it with money:







