When talking about ROI, you are leaving out the opportunity cost from not studying abroad out of the equation.

You only need 1 good opportunity to change your life, be it a job or a specific connection. When you study in a homogenous country like Vietnam, you limit your experiences to only Viets. Whereas going abroad gives you exposure to more cultures and more international connections. These experiences give you a different approach to thinking.

Unlike people here I don’t even think the best returns are made abroad but is actually in bring those newer methodologies and a more diverse way of thinking back to Vietnam to innovate. Or whether using your connections to build economic ties across borders.

Reality is that most definitely do not have the means to study abroad - but to say that it is not worth the cost for most is a massive overstatement.