Why have your cake and eat it? It gives more people from poor countries to experience Japan and earn money there. Then they come back and have money to open bus

Why have your cake and eat it? It gives more people from poor countries to experience Japan and earn money there. Then they come back and have money to open businesses and more knowledge and exposure to first world practices. It also distribute the opportunity between more people rather than giving everything to few lucky ones while the rest don't get any opportunity to improve their lives. It also prevents all the obvious problems of integration and fractured society which affects second generation immigrants in many western countries. It's a win win situation for everybody.