Not at all. By far the biggest engine of emigration is money. In my country (Romania) there are millions of people working in western Europe (2 million in Spain, 1 million in Italy, probably something similar in the UK + Germany + France). A large number of them are parents who leave their children at home and work for most of the year there to gather money.

Even if you're talking about just software devs, people still move to the west for higher salaries, though I believe there is more movement towards the US, especially since the software industry has a lot of local branches of US companies.

But I can tell you from the ground that at least the common perception is that you are generally going to be wealthier as a software developer in western Europe than in Romania, even though in Romania software devs tend to be much better off than the majority of the workforce (and even though software devs in Romania don't pay income tax on their salaries, which is a nice 15% rebate).