To a proponent of Leave, Brexit is intended to recreate a highly cleaned up version of Victorian England–a green and pleasant land filled with sheep, stone churches, thriving high streets, and picturesque villages. In the eyes of these people, a vote for Remain will result in a nightmare version of the status quo: a land overrun by immigrants, some of them terrorists, run in the interests of vampire squid London bankers and grasping Brussels bureaucrats.
To a Remain supporter, the defeat of Brexit means that England will continue on its current path to become a wealthy, dynamic, cosmopolitan, multi-cultural nation. If Brexit passes, England will decay into a stodgy, dull, and less prosperous monoculture–think of a more secular version of the Republic of Ireland in the middle of the 20th Century.
The Leave vision is easier to sell and grasp, particularly for the elderly and people living outside of the Greater London area. I suspect that is why Brexit could pass in spite of the fact that there is no reasonable economic case for it.