Edit: And I don't find it to be a moving counter argument. Additionally, I'm not sure its a good apples-to-apples comparison as the phenomenon seems to be prevalent among US ex-patriots, rather than the entire population.
Edit2: It turns out that it's hard to know how many americans live overseas[0], but it seems like 6.8 million might be a good guess. 4.2k / 6.8m is still only about .0006% though.
[0] http://www.migrationpolicy.org/article/counting-uncountable-...
Nitpick: the word you're looking for is “expatriates”. Although this one made me smile :).
http://www.nbcnews.com/news/world/why-american-students-are-...
It's very unlikely that the uptick in expatriation is due to a recent increase in the number of US students enrolled overseas. It takes 6-8 years of residency to get German citizenship, and while I don't know the details for Germany, in Sweden that excludes residency as a student.
That doesn't sound any slower than the US - it'll probably take me around 8 years of post-student residency to become a US citizen (3 on H1-B, then 5 on a green card - and bear in mind it's much faster for me than for someone born in India or China, who face massively backlogged green card quotas).
A lot of people fixate on citizenship, but permanent residency is 99% as good as citizenship. Ask any green card holder, they'll tell you the real challenge is getting the green card. The subsequent 5 year wait for US citizenship is gravy by comparison.
While permanent residency might be a possible substitute, the lack of any citizenship will likely make it more difficult to travel to another country, and there may be legal problems should you have a child as a stateless mother.
He didn't say that it was.
Likely not. If they're so angry at paying taxes to the country that helped them build their wealth, they're likely already employing several other ways to cheat on taxes.
[1] For any length of time; so not comparing to, say, the National Socialist bubble in Germany, 1933-1945.