While the short-term economic consequences of Brexit are not to be dismissed, it is the impending failure of the European project that should provoke the bigger sense of concern.  The EU's two biggest achievements since the establishment of the single market -- the euro and border-free travel -- are both under threat. These implosions would be a magnitude more painful than the British vote.

The two are closely linked. European governments realized in the 1980s that competitive currency devaluations were hindering the single market, which was supposed to bring more industrial specialization and economies of scale. A single currency, they hoped, would put an end to that game, bring low German interest rates to all and enable national governments to reduce deficit and debt levels, as enshrined in the Maastricht criteria.

But there would be a cost: Respecting these rules would create political pain as parts of the labor force were displaced. That is where the 1985 Schengen Agreement came in. The pain of fiscal restraint and adjustment would be eased by promoting free movement. People might lose their jobs in Fiat, but they could go and work in the Ruhr. The single market had already enshrined this freedom, but Schengen made it truly palpable by removing border controls.

Over time, cross-border trade, tourism and labor mobility increased markedly as a result. The freedom to retire, go on holiday or study in another EU country created important political constituencies in support of Europe. As Eurobarometer polls consistently showed, border-free travel was hugely popular. Both the euro and Schengen are now on life support.

David Fuller's view

It has long been basic economics 101 that you do not introduce a single currency before creating a federal state, which of course, the vast majority of citizens in Europe have never wanted.  The EU’s political founders and followers ignored this reality by introducing the Euro, bankrupting Southern European countries in the process.  The EU will never recover from this in its present form.

Europe can still have freedom of movement with travel and residency agreements between consenting countries.  I do not see why countries could not reintroduce their former currencies, over which they would regain full control.  While travelling, they could use the Euro like Bitcoin for expenses within other European countries, if they did not want to convert currencies every time they entered another European country, as in the pre-Euro era. In other words, the Euro would no longer be a national and regional reserve currency.  Instead, it would just be a commercial currency which anyone could buy, sell or hold, should they wish to do so.