Imagine the US going through a Greece episode, which was caused in big part by tax avoidance. To this day it's perfectly fine in Greece to ask for a ~20% "cash discount" in almost any shop, which of course means simply not paying the VAT tax (similar to the US sales tax).
Edit: let me self-correct - this does not seem to be an actual problem in the US - with this plot: https://en.m.wikipedia.org/wiki/Tax_evasion#Government_respo...