It's Japan, that's as a closed of a system as you'll ever get. You're also giving it to a majority of the population and add to the fact that 0-60 represents almost the entire labor force which for a nation represents the vast majority of the disposable income an economy would generate, you might as well call it the entire population. Heck, does it even matter if its not the whole population?
So suddenly everyone is rich today. What do you think their first action would be? Quit their jobs. So when I get hungry and want to eat, who is going to fling my burgers? No one, they all quit. OK, so I'll make my own burgers. So who do I buy my food from? No one, they all quit. So how do I get a work force to get back to work if they're rich? I have to pay them an appropriate amount that they would be willing to work. But in order for me to pay them that amount, the customer would also have to be willing to pay an appropriate amount to get them to work and don't forget, no one actually earned this money so they have no respect for it and spend it without abandon. Eventually, the market would correct itself so that I can pay employees enough to make them want to work while at the same time, customers would be willing to pay enough for the goods/services. Now, you could argue that Japan would allow immigrants to work in their stead, but that won't happen. 1st, Japan is extremely xenophobic so its unlikely to happen. 2nd, how are they going to get there? Remember, they all quit. That last part is no joke, if enough people in key positions quit, everything can and will fall apart. And why wouldn't they quit? No one likes their jobs and no one likes working.
So lets assume it wasn't the whole population... Yay! We have ourselves some burger flippers... Thank god, I was gonna starve... Or not. Why would I flip burgers? Millions of high paying jobs just opened up and while I may lack skills necessary for that position normally, those businesses have a choice: Hire me or hire someone else who is equally less qualified... or not hire anyone and go under because they can't function properly. So again, we have a problem where the positions need filling and in order to fill them, we need to raise the incentive. Same results regardless.