UK industry needs the EU market far more than the EU industry needs the UK market, simply due to the size disparity.
Not to mention that while indisputably the UK currently is a net payer into EU funds, if they don't pay money anymore they will get less benefits out of the deal too.
It would be delusional to assume that they will keep all the benefits while ridding themselves of most of the obligations.
That's just not going to happen, something will have to give.
Another point is that the EU has all the incentives to not give the UK a sweet deal, because that would otherwise encourage other countries to exit as well.
The UK will obviously lose the "benefits" of EU membership, but it was a net contributor in financial terms. All else being equal, the UK could replace all EU funds spent in the UK, and have cash to spare.
In trade terms, the EU faces a prisoner's dilemma. It may be beneficial for them as a whole to play hardball with the UK, but major exporters to the UK (e.g. German car manufacturers) won't accept it. There'll be some diplomatic bravado, some tense negotiations, and the UK will be granted access to the common market.
Nope, as I previously commented [1], there is no room for giving new benefits for free as it will cost the EU its existence.
I think a consequence might be that trade with Russia will be reopened. The US influence in Europe has been lessened with the departure of the UK.
Also, did you think about the buying power of the UK? The mortgages stand, but the prices will going down as the pound looses it value. In periods of uncertainty trade will fall as will investments. Those we can afford quality goods from EU might still want to buy it (eg. luxurious cars from Germany).
If the pound loses value in the medium-run, foreign investment in the UK will increase.
Brexit, if negotiations are acrimonious, will be worse for the EU than it will be for the UK, so I don't expect much of a long-term shift in the GBP-EUR exchange rate.
Outside the EU, the UK can make itself an even more attractive place to do business, no longer hampered by EU laws and regulations.
In any case, I think Brexit will be curtains for the current incarnation of the EU. It will either have to reinvent itself significantly, or collapse and be replaced by a new union.
Not to mention that while indisputably the UK currently is a net payer into EU funds, if they don't pay money anymore they will get less benefits out of the deal too.
It would be delusional to assume that they will keep all the benefits while ridding themselves of most of the obligations.
That's just not going to happen, something will have to give.
Another point is that the EU has all the incentives to not give the UK a sweet deal, because that would otherwise encourage other countries to exit as well.