Ask Israel about the wall....works for them.
Here’s the problem with your example.
1. Israel’s wall do not have millions of customers on the other side of the wall.
2. There are no incentives in climbing, digging or going around that wall.
3. Located in densely populated area.
So basically you're admitting their wall works but are grasping at straws to try to defend your very weak argument.
Ok fair enough.
However, yes, they have a ton of people on one side trying to get over. They don't have MILLIONS, but neither do we. And yes, there are incentives to get over the wall, they are getting away from terrorist nations.