I do not think it is possible to return to nation states, as it was in Europe under the Westphalian system. We are talking about something else. No one will allow a Europe in the same condition that it was before the beginning of the integration process to exist. I think we can see further very scary processes for Europe, a real civil war. As the British are out of the EU, but they are not out of the migration policy crisis, which will continue to attack, it is not out of ultraliberal values.
In my opinion, the British did not suffer much from Europe. Yes, they did not like some things. In fact, the EU without England is a different European Union now. If it would be preserved without England, if it began to move towards truly continental European interests, it would have a chance. But this will not simply happen.