Surely, immigration is good for the home country of the emigrants economically speaking (think remittances, entrepreneurs going back, etc). This, I'd argue, is indeed better than foreign aid. But what Romer is arguing is that his model is meant to change the rules and bring the ideas to the country. As an immigrant, what would be the point of moving to Canada and learning new models/ideas if when you go back, you won't have the power to change them and expose others to them under the same circumstances?
Surely, immigration is good for the home country of the emigrants economically speaking (think remittances, entrepreneurs going back, etc). This, I'd argue, is indeed better than foreign aid. But what Romer is arguing is that his model is meant to change the rules and bring the ideas to the country. As an immigrant, what would be the point of moving to Canada and learning new models/ideas if when you go back, you won't have the power to change them and expose others to them under the same circumstances?