Im inclined to think the Nation State is done for. With increased globalization (and you are quite right, money has no country) the nation state is actually increasingly useless for anything except killing foreign enemies. Oh, and football, lets not forget that.
So Brexit, looked in that light, is a return to the past. The Irony is, I see what the EU is doing, trying to build a nation state apparently, is also somewhat doomed to failure. Its like inventing the worlds finest steam engine, just as the world is transitioning to Diesel.
We all look at the world through past experience, but the digitization of the past 30 years is pretty much tearing up the rulebook, just as surely as the Printing Press ripped up the ascendancy of the Catholic Church in the 16th Century. And just as then, or just as during the Industrial revolution, nobody has the faintest idea what is going to happen next. Its clear viewed like that, Brexit is a backward step. The problem is, I still cannot conceive of the EU as a forward one either.
Its a fascinating and terrifying time to be alive I think.
The nation state is not dying by any means, ask China. What has changed is the economic paradigm, something that has happened a number of time before. Most profit, some suffer. Now, on this Brexit thing, the issue is less one of leaving vs how to leave with minimum pain.
Instead of accepting compromises with the EU (that the EU would love to accept like freedom of movement for EU nationals) the current HMG has taken an erratic path that seems to achieve maximum damage and them corporations that create employment in the Southeast are left with no choice but to unseat, and all those jobs occupied by non-Ukians are not going to be there for Ukians.
The UK will remain a significant market, so you will see Jaguars around not made in Germany, but the platform will be smaller.