That does not mean it makes sense to spend 10's of billions of dollars on a wall that will only make things worse...

Those numbers you give are from Federation for American Immigration Reform (FAIR) an anti-immigration 'think-tank'... there is more to the issue...

According to the California department of food and agriculture, agriculture is a 43 billion dollar industry that generates 100 billion in related economic activity... now, what would happen to all that if you deported all those illegal immigrants?

Personally I think the the solution is to penalize the businesses that exploit illegal immigrants- force them to pay them enough that Americans would find it worthwhile to work those hard jobs... but that will never happen. Instead you find it easier and more satisfying to vilify those human beings as parasites... to blame them for your own inadequacies... "They are the reason I don't earn more" etc...