[rover0]

Adding more reasons:

Europe as a single entity is problematic, there's a north-south gradient, the cold war east-west divide, and EU/non EU.

* Switching jobs was less common, there used to be loyalty from both sides.

* It's easy to get competent workers from outside of "western" europe with a matching culture and timezone. I've seen a switch from outsourcing to poland(former east) to the ukraine(non EU+east). This is good for the polish guys, they're almost at our level now.

* Residence requirements for people outside of the European continent are low, and on base wage mostly lower than for any other sector.

This makes the wages more internationally competitive from a business perspective, and hooks into "Individual contributors in Europe are not as valued as much as managerial professions" Because you can get the work from somewhere else cheaper.