I find the whole argument X needs Y foolish. It is so much similar to Donald Trump's China hatred.
Members of EU benefit every-time they export something to a large market such as UK (e.g. Cars). Members of EU benefit each time they willingly import something from UK (e.g. Tea). Either ways if EU wants to protect interests of its members it makes sense to trade with UK just the way it did in past. Any "revenge" is likely to hurt EU members whether or not it hurts UK.
UK survived before EU and will continue to survive beyond EU too. In fact I think with better immigration policies and freedom from red tape of EU, UK will be better off economically. The very presence of EU in my opinion is against principles of democracy. People of England basically accepted restrictions coming from Brussels who were not voted for by them.
>In exchange for access to the common market, Britain had to accept an external tariff and, over time, a deluge of regulations from power-hungry Brussels. The former makes imports more expensive in Britain, while the latter makes British exports less competitive globally.
> Jean-Claude Juncker, the current president of the EU Commission, summed up the decision-making behind the introduction of the single currency thusly: "We decide on something, leave it lying around and wait and see what happens. If no one kicks up a fuss, because most people don't understand what has been decided, we continue step by step until there is no turning back." [1]
[1] http://humanprogress.org/blog/britains-democracy-is-a-sham