Answer:
it costs money to print money and it costs a lot of resources
they can but the last time a country just decided to print money was Germany diuring world war 1 the more money a counntry prints the less the money is worth in Germany during world war 1 they printed so much more money to reverse the war debt that they cased inflation which is more money of less value because of the inflation people would take a wheelbarrow full of money just to buy a loaf of bread and some milk because the money is so worthless.