How many people would now leave their countries if there were no borders?

Many, I believe. Without borders, people would be allowed to move freely to the areas with the best opportunities. With the borders and immigration rules as they are, many people are deterred from moving and seeking different options. Moving to a different country, gaining citizenship, and becoming employed is a long, expensive, and difficult process. Many countries also do not allow migration without a citizen sponsor and/or immigration lawyer, which further complicates the process. If there were no world borders, I believe almost every person in the world would seek a setting where they were offered the best and safest opportunities, regardless of location.