Instead of shooting the people coming over the border, take out the cartels and the Mexican leadership, annex the country and stabilize it. Make it another Puerto Rico. Let the investment banks and US Multinationals run it. Hyatt and Wynn can run the hotels, Altira and Down can run the drug business.
Give the Mexican people a safe and decent place to call home
Umm, NO (that's an act of war)
Our Nation is tens of trillions in debt and borrowing hand over fist. What you are proposing is what personal charitable giving is for and what entrepreneurial investment is all about. The US's Constitutional responsibility is to the protection of its citizenry (not other's citizenry) from threats both foreign and domestic. Secondarily, facilitating the prosperity of the citizenry in a geopolitical word.
If we actually wanted to stem the tide it's hardly a daunting endeavor. I recently bought another German Shepherd and in doing research between sires in Germany (don't like the US breeding genetics) I looked into BDR shepherds (Bundes Deutschland Republic) which were bred as high energy work dogs, chained on long leads &/or running free along the wall. They were kept half starved, to rip apart any E Germans from mere contact with the wall. All this to say that if we want a secure border it is hardly an impossible endeavor even with antiquated methods (a wall, machine gun turrets & BDR type dogs running free along the wall) lol. Add live satellite imaging, heat imaging, ground sensing units star wars laser tech. from China (ok yes, I'm having too much fun here) we can do more than slow down the in invading horde.