[ska]

That doesn't mean you have to have much added complexity. The complexity doesn't really come from adding sources, it comes from adding exemptions and credits.

e.g. an overly simplistic tax code could read: everyone pays 18% on all income. All money you get from any source is income.

Now clearly that has some problems - but complexity isn't one of them.

Reporting and fraud are separate issues, or at least separable ones.