> People don't do this because it leaves tons of money on the table.

In my country I literally got a letter from the government if I could please file my taxes, because they believe the automatic deductions are too high so I am likely owed a back payment. In a previous year (I am not very good with non-timing-critical paperwork) they even called me on my personal cell to inform me about something similar.

The slogan of our tax collection agency is "we can't make it more enjoyable, we can only make it easier". If you're a regular employee and your taxes - deductibles or not - are a hassle, then that's 100% a political choice.