This now puts almost the entire economic burden of the EU on Germany.
Good luck negotiating trade deals with the EU after deciding to leave, i'd be willing to bet the EU is going to negotiate HARD with the UK as punishment for leaving, make it hurt hard, and make it noticeable, it's the only way to protect the EU image, especially with all the commentators talking about the start of the fall of the EU.
Punish the UK so other countries aren't tempted to follow.
Besides, the UK imported far more from the EU than it exported, it may have provided decent amounts of cash, but the benefits were free trade with the EU, which is worth far more than they were paying.