There is a sizeable brain drain, but it's not really that large, especially when you consider that you can get half of an American salary in an outsourcing firm while living somewhere where cost of living is a fifth of what it's in America (numbers out of my ass, but you get the idea). The poor nation also gets oversea investors who want to have things done cheaply and strong labor laws ensure you won't have the Chinese situation of people working as more or less slaves.
Of course that doesn't hold true for all occupations. Doctors being a sore point, for one - they can't make what they would abroad mostly because most of the people are still paid miserable wages and won't be able to afford healthcare which would pay really high salaries to doctors.
At least in the case of Baltics cost of living is not a fifth of what it is in the US. In fact it could even be considered similar. For some reason countries like Spain and Germany have CHEAPER cost of living for day to day things (except rent).
Quality of life is just worse in those regions. It's not very much, but still noticeable. One of the reasons why this is the case is just income being lower for equivalent work. Richer countries just tend to have the better companies with more reach.
Of course that doesn't hold true for all occupations. Doctors being a sore point, for one - they can't make what they would abroad mostly because most of the people are still paid miserable wages and won't be able to afford healthcare which would pay really high salaries to doctors.