[DenisM]

>my (highly-skilled) French friends do not plan to return in the foreseeable future

Selection bias alert! You're more likely to meet people who swore to never return than those don't mind returning.

[epsylon]

Not to mention the fact that software engineering salaries are notoriously low in France compared to the US. Thus most people who have emigrated have strong financial incentives to stay there. (Well, at least until they have cancer and crappy insurance or they have to send their kids to college)