If I was a government body responsible for setting tax rules after reading the article I still haven't learned anything. First of all, tax systems are typically result of huge forces within the country and represent history of negotiating between parties or other groups of people that each tries to get something for themselves while the government needs to deal with finite budget and groups of people dissatisfied tha…
Most people who have just one job end up paying exactly the right amount of tax (that 1 line in my spreadsheet) and don't need to file - if you have multiple jobs you may get money back (depending on how you registered your second job) if you don't file the IRD will send you a cheque (we don't do cheques any more, they'll drop it in your bank account).
It doesn't have anything to do with GDP, we used to have that complex tax system, about 30 years ago we chose to change it - what it takes is politicians with the political will to change things