Eh, I think you could teach 90% of how taxes on wages, investments, and property work in a simple class for teenagers. It's the other 10% that takes years of study and legal expertise--but the vast majority of people don't need that 10% more than a few times in their lives (e.g. if they get very rich, retire, have to handle a complex family financial situation, or are otherwise massive outliers), and hiring a tax attorney at those times is probably a good idea regardless of whether or not you learned the basics in school.