> While a tax seems like an easy fix, it may also cause the government to come to rely on income from plastic acting as a deterrent to law-making which discourages the use of plastics.

I don't know how common such a thing is, but in Washington state if a tax is labeled as a "fee", it must be earmarked for a specific purpose. If we put a "plastic fee" on products packaged with single-use plastics, and then mandated the raised funds be used to clean up plastic waste, that could be a good way to avoid that very likely outcome.