While I don't feel that there is risk of brain drain because of the reasons listed in the article, I do believe there is that risk. To be honest, even though many European countries don't pay as much as the US for the same job, I found much more comfort around the ideas pushed in those countries. The culture I found in Sweden for instance is one that is much better for the employees than the fast-paced top-gun style…
Europeans often have this illusion of a working social democracy compared to the US suggesting their by default offered benefits to be superior to the offers from the US. That's not the case. In a lot of middle-income-class positions you get most of the things you described as perks. Health care support check. Additional vac days check. Plus a much bigger paycheck.
Surely I can agree with treating the workers well and in my book this equals with not exploiting them (so no excessive overtimes, phone calls, onduties etc). But this is not a universal thing in Europe you cannot really generalize this and a lot of the EU companies can be very exploitative even if it's ILLEGAL.