Tax evasion is a common problem and if we say in general the government is easily viewed as inefficient in every task it performs and this forms a cost as well.  The best solution that I've heard of for this continual problem is the universal basic income where all citizens receive a very basic wage from the state regardless of their other factors or job income or assets or circumstances.   Then the tax extracted is mostly via a sales tax or scalable % based on non essential goods.   People who spend money to carry on living such as food should not be taxed as its not an optional activity but its fairly justifiable to tax luxury goods to service the state.   
   Also a direct tax like this makes the expenditure of the government far more clear as a burden upon the nation and the people.   This is an important feedback effect that should help control some of the endless spending and inefficiency in the government.


This is the status quo, its already true that governments are financing themselves by over producing currency and handing it to themselves via low interest debt.    The main reason this is a problem is it leads to confusion and distortion of the economy.   There is a negative and a cost to destabilizing the value of the nations currency, it will cause inefficiency and instability which is hard to measure but causes the risk of bubbles and crashes in asset prices from overly loose monetary policy.