>But what about a scenario in which for 30-50 million Americans file for their taxes by sending a SMS (as it's apparently done in Scandinavian countries)? And all the other taxpayers, they're wondering: "Why the f-ck can't my taxes be that easy??"
How does your independent consultancy cram all of its income and expenditure items into an SMS?
Less snark version: the main cause of complicated tax code is needing to have rules about how much you can deduct for an expense when determining net income (for entities taxed by net rather than gross income, like corporations and independent contractors), not from special credits or varying rate schedules.
That problem, in turn, is amplified by the size of the taxes, which gives people an incentive to abuse whatever leeway is given by the deduction rules, forcing them to be more precise, leading tax experts to abuse the new language, and so on.
Btw, just did my taxes. Did you know that the cost of classes to change your career or improve earnings isn't deductible unless it's from an institution on an approved list?