The problem is , there are very few Europeans or EUans. There are French and Germans and Spanish etc; they all want their country first and sure open markets but their country first. That is how they vote (certainly these days). Most people do not feel EU unfortunately. Language is one thing: it is getting better but having language not unified (English, Spanish, Mandarin; pick one) is a massive and real issue keeping people's minds and efforts local instead of, at least EU wide. It is slowly getting better but the EU should made easier accessible and far higher funds for pan EU projects. Currently it is a serious pain to get access to EU funds and many just get eaten by the few massive consultancy corps who have dedicated teams going for any funding and tender in any locality and language.

It's more a risk management issue. A country that wants to do everything by itself (from food, to shovels, to cars, to computers) will not be the most efficient and will loose a lot. Before '90s communist countries were "proud" that everything was produced locally - except many things were breaking or bad quality or unavailable (not all, but many).

I would claim that today is a much better moment to switch than it was 20 years ago - much more open source options, so less overall costs.