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.
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.