Economic development? Which countries?

Erm, all of european states are quite better off, than their neighbors?

First two have been utter disasters however, and are directly affecting people on a daily basis now. Here in Scandinavia it’s coming to a head but it’s a similar story further south, in Germany in particular.

Oh look a brexiteer brain. What exactly is the problem with reedom of movement and trade for EU citizens?

Immigration, which I assume is what you’re hinting at, has nothing to do with open borders between EU states.

Unchecked cheap labor from eastern european countries has had a dramatic effect. That's directly related. But illegal immigration also does because the moment you get in to one lax EU country with open borders to another, your movement is a lot easier.

I live this reality and have family in law enforcement. You might not want to believe it but it's absolutely the truth on the ground. We need to control our borders much more strictly.

At least for Germany that situation is not imposed by the EU but is entirely due to the choices of the local politicians.