So we could buy a thousand Blackhawks for ten billion. That's one every 22 miles of border. Assuming a life of 30 years that's 330 million a year. Multiply by ten for crew, maintenance and support, thats 3.3 billion a year.
Big deal.
Mission availability of the UH-60 is between 50-60% under optimal conditions. However, if there are any 250,000-watt radio stations in Mexico that are close to the border, that stretch of border is closed to the Blackhawks for safety reasons (the flight controls tend to go batty around commercial radio stations of much lower ERP).