Because the Leave vote is not a UKIP vote. That is just something the Remain campaign chose to repeat ad nauseum, as if that would make it true. Or do really believe that everyone who is not Scottish, Irish or lives in London is a raging racist?
What will happen is that businesses will do what businesses have always done: talk to buyers.suppliers, make deals and then sell/buy.
We will all continue to breath, in and then out. Walk, talk, sing, play, sleep, get up in the morning and go to work, school, etc.
Shockingly, there may be very little difference to the average person. Jobs will be won/lost, businesses will hrive/go bust. People on both sides will claim/blame each other for all of it.
But it might take longer if those disappointed with the result carry on telling the world and his dog what a useless, broken, racist country we are!