Britain becomes a “third country” by default in terms of the relationship with the EU
OK.
This will drop the U.K. out of every single arrangement, pact and treaty, from tariffs, freedom of movement, foodstuffs and data
OK, that's known.
Specific deals with aviation, police and security will cease
OK
Every single element will then have to be re-agreed
But we already know this.
And you don't think arrangements like this and for all the above are not in hand?
Remember, our leaving creates headaches for EU member states too, who will NOT want to put up barriers against Britain, our tourism euros, our security services, and international cooperation regarding crime and terrorism. I imagine it is not going to be terribly difficult to engage on the same, mutually agreeable terms, if they are desirable for all parties. Why would anyone want to upset arrangements of mutual benefit? Only the spiteful would play games 'because we have left the EU.'
We leave a trading bloc, not a continent and in terms of international cooperation only the idiotic/dense would pull up the drawbridge.
The U.K. will default to WTO terms
We already know them and use them, as does the EU. That eventuality, if it happens, will already have been investigated and explored with WTO bodies.
We won't suddenly start floundering and panicking on November 1st, much as you'd like us to, for having the temerity to leave.
Managers prepare for all eventualities. You can rest assured the UK has specialist negotiators already dealing with issues that will need to be re-arranged. Brussels and EU member states will be doing the same.
I don't see enmity between the UK and the EU. We just want to work differently, outside the restrictive (and expensive) EU. We no longer want to be liable for the collapse of the unstable Euro either, to the tune of £200 billion, or more.
We will manage the impact. We wanted out, and we know the work which has to be done.