My evidence in purely anecdotal, but I've been a developer for a long time now (working on 13 years professionally) and have worked with tons of developers from India, both remotely (overseas) and locally hired.
What I have seen are people who claim to have masters degrees but are utterly incompetent - I've seen them trying to solve extremely simple problems by calling into some sort of support number and having someone in India (I assume) walk them through the problem remotely and tell them what to type into the IDE. Seriously.
I've had to deal with guys who were so unbelievably arrogant (apparently they were some sort of royalty in India) they couldn't sit and listen through an entire sentence without interrupting, yelling and generally making asses out of themselves. And this was when they were asking me for help! It takes almost superhuman patience to deal with.
In 13 years I've only ever met one programmer from India whom I would consider competent (and he was actually much smarter than I am) but he was such a jerk it was impossible to have a discussion with him, even to explain basic requirements.
I used to think that this was just a cultural thing, or a language barrier, or that I was just working with the worst people - getting unlucky - but over the years it has just gotten worse, not better.
I've been waiting patiently for the backlash against outsourcing to develop as businesses realize that the cost of outsourcing projects is actually 3X not 1/3, but while I've seen a very mild trend toward this - it hasn't been anything like the tidal wave I'm expecting.
To be fair, I'm pretty disappointed with the American programmers I've worked with as well (with some notable exceptions), but by and large I've been able to work with them, explain issues, have issues explained to me and eventually get the job done.
I think there is a fundamental problem in software development today (here comes the 'get off my lawn' rant) that is not localized to any one country: programmers aren't nerds anymore.
See, in the old days (back when I was a kid) programming was magical and elite and only the best and brightest would even try. It was new and respected, and drew the types of people who were willing to spend endless hours painstakingly gnawing at a problem until they had a solution - then deleting it all and redoing it when they discovered a better one; and this was done for fun, as a hobby!
Now (like so many other things) businesses try to commoditize it, fit it into rigid processes, categorize and quantify it. I can understand the impetus and motivation behind this: as a business it sucks to be dependent on magicians and magic - but I think it has lead to a decline in talent locally and globally.
A business would generally rather have a predictable, repeatable process - even if it costs 5-10 times as much - than to be forced to rely on individual talented people. I guess I shouldn't be surprised that there is a global market claiming that they can provide that sort of predictability and dependability, and that businesses are naive enough to believe it.