I have another take besides that which is purely political.
The economic outcome is largely in the hands of the umpteen businesses within the UK and the EU countries that do business on a daily basis
Yesterday I posted a blurb describing the heavy presence of the German firm Seimens in numerous UK locations. Is Seimens going to abandon all that UK presence? I think not. The same principle holds for many many other businesses.
The businesses that operate on a global scale will continue and work it out. Accommodations will be reached simply because there is money involved.
The creation of the EU was actually one of the "accommodations" you described.
If the businesses that operate on a global scale can't get their crony capitalism through unelected EU bureaucrats, they'll get it through elected leaders.
Like they do here in the U.S.