What do Brexiteers believe would happen to the 27 countries of the EU if the alliance collapses, and everyone is left to fend for themselves in very harsh economic conditions. and left out of major deals with USA, Russia and perhaps China? If each and everyone makes own rules on safety of goods, agriculture, animal welfare and transport, utilities (remember most of our are now owned by EU and other countries), air safety, nuclear safety, without a strong NATO, without extradiction of major criminals and terrorists, etc, etc, etc, etc, etc, etc, etc.
The floor is all yours as I'd be very interested to know how you see it pan out (personally I am quite terrified)