Are you serious? Do you actually believe that Mexicans are a net benefit to the US? Tell me this: Mexico has a lot more Mexicans than the US does; if Mexicans are so good for the economy why isn't Mexico rich?
You are entitled to believe what you want to believe.
If you cannot see that foreign workers are here because of our low birth rate, there is nothing more to be said.
If you cannot see or understand future demographic trends, you will never understand what is happening.
As for the U-Hauls, I don't have time to lookup the demographic data on that. What percentage of the population uses U-Haul?