There would most likely be a big opportunity with President Trump/USA trade deal.
And couldn’t the UK also do deals with Mexico, Japan, Vietnam, India, and others? Is there some reason why not?
And surely West Virginia is part of one country—USA. But the participants you speak of in the EU are each separate, individual countries. Each country can stand on its own and has for hundreds of years before the EU existed.
There would most likely be a big opportunity with President Trump/USA trade deal. -- definitely. Yet the USA currently accounts for 12% of UK trade and the USA runs a massive surplus against the UK. Even with the best opportunity, that can at best double.
The rest of the EU accounts for 54% of UK trade. The USA isn't going to replace that.
More critically - the UK has little that it makes that the USA wants -- that 12% is mostly imports from the US to the UK.
And couldn’t the UK also do deals with Mexico, Japan, Vietnam, India, and others? Is there some reason why not? -- it could, but again, what does it have to offer?
India has already said it wants more open immigration for its nationals as quid pro quo for trade
Japan has said that leaving the EU will be bad as many Japanese companies WERE using the UK as a gateway to Europe. With Brexit, companies like Honda, Nissan and others are shifting operations to Ireland or the Netherlands or even Germany
Vietnam - now the EU has signed a deal with Vietnam. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/790325/Impact-of-the-EU-Vietnam-free-trade-agreement-on-the-UK-economy.pdf -- that doesn't automatically roll over, the UK will need to renegotiate and they will have a weaker hand compared to when they were part of the EU. Expect more to be leveraged out of the UK, but yes, that will be good
Mexico - In 2018, two-way trade between Mexico and the UK reached over $4.6 billion USD. Mexico exports to the UK include: gold, automobile parts, beer and other electrical equipment. British exports to Mexico include: alcohol, medicine, transistors and various other products. That's a small trade, comparatively the UK trades $127 billion with the USA. And look at the main exports: auto parts, electrical equipment, transistors - all of those are because the UK is part of the Western european supply chain
finally - note that besides the USA the other trade deals will take time - if not years - to complete.
And those deals will be weaker than the trade deals that the UK already has with India, Vietnam, Mexico, Japan etc. as part of the EU
W Virginia was an analogy - and it gives an idea of the enormity of the task of extrication.
The UK is part of the eu confederation, not a state in the union like WV. Yet it has been part of this confederation for 50 years. That is 50 years of joint agreements, regulations, trade deals etc.
all of the trade deals the EU made with India (say) do not roll over to a trade deal India-UK. India will squeeze the UK for more benefits naturally as the UK will have a much weaker hand outside the EU. ditto for a US-UK trade deal or any other
the other part is - what about all the laws that the UK passed based on EU guidelines? Boris said most will roll over and continue in the UK, but is that what the Brexit hardliners want?
Finally - the borders for goods and services. Outside a customs union, you have time spent at borders and added costs associated with that as well as with tariffs
If W Virginia, where I note Cap is from, left, it would have to figure out how to deal with all of these issues. The UK has it easier, but not something that can happen overnight
Each country CAN stand on its own, no doubt - and Scotland and Wales can also stand as independent countries. And even WV could stand as an independent country if it left. However it would take time to implement this
The UK isn't going to descend to the stone age post Brexit, no way, but it will have a dip in GDP and it will have components (Scotland, NI) leaving - reducing it to basically England-Wales
those are things that can be overcome --as Anne Widdecombe, the Brexit party leading member said - the UK can survive returning to the post WWI state.
Too many people were fed a story of a paradisaical economy post Brexit, but even Rees-Mogg later has said that it would take decades to get back tot he 2016 standard of living again