Probably because the government of Spain and Romania have ceded that power to the European Commission, which is appointed by the Council of the European Union not elected.
We don't even know what is going to happen in the real world, that's difficult to make projection in a hypothetical world were the EU was built differently.
For example, would the UK have voted out in the first place in such a world ? Would Turkey be a member of the EU ?
Edit: Let's add a bit more info. The goal of the EU was to become the USA of Europe. Can each State of the USA determine its own immigration rule directly with foreign nations ?