Various countries or communities have tried protectionism. Trouble is, it's like a boomerang. Throw it and it comes back, either TO or AT you. America's tried it, as have older countries. China tried it around the time of the Boxer rebellion, Japan went for it, and Russia in its time. Their economies stagnated. It's the opposite corner of the boxing ring from 'embargo' when your economy is cut off, and the results can be the same:
'Shut me/us out and see what happens!'
You can over-tax, you can ban certain goods, but you can't shut out the outside world for long without it reciprocating. We've tried it in the UK long ago, and when we joined the EU that was a kind of club that gave favourable trading terms to fellow members but older partners - in the Commonwealth - went their own way. If we leave the EU we won't necessarily get them back. We'd have to make concessions that could bite for a while. When we were in EFTA (European Free Trade Association) we could pick and choose.
Edward Heath shut the door on that in 1971 and our EFTA partners either joined the EU or stayed aloof. Austria joined the EU and the Euro-Zone, as did Finland, Ireland, Portugal and Sweden. Denmark joined the EU and stayed out of the Euro, as did we. Norway and Switzerland stayed out of both. Their economies have soared. Greece and Spain are struggling in the Euro-Zone, unable to set their own taxes. Ireland's got down to austerity measures without grumbling (after all, they can just up sticks and come across the sea from Dublin or Dunlaoghaire* as they always have).
* pronounced: Dunlairey