Maybe the small matter that every single economic authority on the matter from our foreign allies like Barack Obama, to the IMF, the Bank Of England, the Confederation of British Industry, (and endless list) said it would be an unmitigated disaster... and then there are the people who think it is a good idea... Trump, Putin, Lafarge, Gove, and not even the the PM thought it was a good idea to start off with. Project Fear? - more like Project Shit Your Pants Now...
Also, every single study bar one, from credible institutions like the London School Of Economics (and indeed HM Treasury), predicted a significant downswing in the UK economy post-Brexit.
The lone study is worth paying attention to. It's from a group calling themselves "Economists For Brexit". It proposes that the UK should, post-Brexit, unilaterally scrap all tariffs. Under those conditions, it predicts a minor rise in the UK's GDP, but notes that it also expects "a sharp rise in inequality".
So basically, everyone credible who has studied Brexit, including the guys calling themselves "Economists For Brexit", reckon that it's going to make the UK worse in some significant way.
It depends on the timescales of the predicted problems. I believe the studies predicted choppy waters whilst the UK divorces from the EU (short to medium term) which in my view is likely. However that's not the same as saying that leaving the EU is in principle bad for the economy.
Secondly there are plenty of economists that think Brexit will work out fine but that is a somewhat unfashionable view so they keep their heads down. Such is the nature of groupthink.
What is it exactly that you think will cause the UK's economic demise?
You could say that all those people have been wrong before and therefore could be wrong this time.
But, the problem you don't mention is that there is an element of self-fulfilling prophecy to those statements. There is no absolute objective metric that measure your country in a negotiation, it is more a market type thing. There is an element of irrationality and if all your partners think you are in trouble, then they will act toward you are if you were in trouble which may well be cause you to be in trouble.
That works at all level too. If enough people living in the UK think the UK is doomed, they will start saving money or investing in foreign countries. A slowing of consumption is a crisis, it does not matter if the slowness was caused by objective and rationale reason or not.
You can already see the effect. The last budget was another austerity budget with cuts and no investment. Despite the supposed economic nirvana that is only a few months away, the government is nevertheless bracing for trouble and that will affect the British people negatively regardless.
