Whatever the short term pain after BREXIT, I'll put my money on the UK surviving a lot longer than the EU in its current state and mindset.
What was a good idea for free trade has become a nightmare of bureaucracy, waste, unaccountability and corruption.
In the same way as was the USSR - a forced and ungovernable collection of different cultures, languages, economies, resources, and regional alliances and distrusts which a bunch of idealogues tried to govern from Moscow with no idea of the reality of real life outside of Moscow and were only able to hold together with an autocratic dictatorship and centralised economic planning.
On the other hand, the USSR did at least have a pretence at democracy which is something the Commissars in Brussels either daren't risk introducing or simply just don't believe in. But ask Russian citizens and citizens of former Russian States whether they preferred the old Soviet lifestyle, or their current lifestyle - the overwhelming majority will tell you that their lives are much better today than when Moscow decided what was best for Russia, Armenia, Estonia, Uzbekistan, etc, etc.
In the end, the USSR collapsed almost overnight because it was too big and too diverse to govern democratically, and if the EU doesn't reform, and reform in a big way, it will simply go the way of the USSR and implode - and better to be on the outside looking on than on the inside trying to get out when it happens.