France, Germany and the UK.

The EU will have a ton less money to prop up other very weak member economies.

The UK will have no problem getting trade deals completed with other countries around the world as well as those in the EU (as much as they bluster about it now). They are the worlds 5th largest economy with ties everywhere.

If the EU really tries to "punish" the UK, others will be all the more likely to leave, and the UK will likely support them leaving.