I think they'd be able to learn. In fact, I'd say I'm sure they could learn.
Keep in mind, there isn't much incentive to learn US law when it's illegal for you to practice in the US. If the US allowed foreign graduates to sit for the bar and provided a visa and path to a green card to anyone who managed to pass and hold down employment, I think many foreign law schools would appear. Many would fail, but many would pass, and some would be very talented. Honestly, I don't think it would be all that different from software development, though I suppose the bar requirement would probably establish a higher floor than you see in programming.
You realize there are huge outsourcing industries (in the legal and accounting sector among others) where workers in India, China, etc. are trained to learn American standards, etc.
And the BAR, like any other "professional" "over-seeing" monopolistic organization isn't about to reduce it's own members value... just like the AMA, Teacher's Unions, ETC. When certification(s) is/are required [to practice], those that have the certifications have a vested interest in limiting the access to said certification(s). It's all a legal racket.
Here's how it works:
I know the law of Australia, Hong Kong, China, and the U.S. However, I only advise clients about U.S. law.
Why? Because I'm liable for malpractice if I get it wrong. Unless I'm willing to religiously follow the legal developments of X other nations, I would not be willing to take the risk of the law having changed since I last check it. And if I were the kind of person anal enough to follow legal developments in other countries, my skills would be in such demand that only megacorporations could afford my services.
