The problem is we've made some changes to it over the years. I think it's easier to just restructure the tax code with a commission rather than to try and patch together a tax code including the differences we have from the real world.
Also, we should be differentiating ourselves from the US government. We have plenty of differences already, I don't see why we HAVE to assume we're exactly the same. We're an independent game, we should make our own events and our own institutions.
Just my 2 cents, sorry.