The solution to open borders is to only allow it when countries agree to our property laws. Right now Mexicans can come here, work sub-minimum wage but also avoid income taxes and other things involved in creating our cost of living, and have the option between living and working in the USA or Mexico. Or working in the USA and living in Mexico. Or vice versa. Basically, they're able to double-dip, and we've even seen that they've started self-deporting more once they hit equilibrium with our job market. The ones that come just to work and send cash back home aren't even welfare leeches, but they exploit a system that we aren't able to. If Americans were able to do the opposite, using our excess of cash/goods rather than labor to move south of the border, buy cheap Mexican real-estate and live inexpensively, without being deported, killed by cartel without being able to defend ourselves, being able to do anything without being shaken down by crooked cops, it would be an amazing thing. Some liberals would call it gentrification, but oh well.
A lot of right-wing people criticize the EU, but I think when you have Poles moving to the UK, working harder and finding a better economic situation for themselves (and therefore, their employers), it's a great thing. Same when old Brits move down to Spain to retire. What it does is reveal and equalize disparities between borders, and in theory should encourage nations to adjust their laws to maximize the value their own citizens can find. We need a neo-colonialist world.