What always amazes is me is when people think it is possible to be told what their world will look like if we leave.
The answer is that it will largely the same as it does now, just as it will if we remain. But they want the fine detail and no one can give them for leave because they do not have any better a crystal ball than if we stay.
If we leave, then the EU will have less money to play with and France will push for much closer integration so that the euro has a hope of working. Maybe this will work against all the odds, but more likely, it will be the last straw for less committed states and they will begin to make a move to leave too. That may well cause the disintegration of the EU and what that will mean for any of the other 27 countries, or for us, no one knows.
On the other hand, if we stay, France will still push for closer integration to make the EU work, the EU migrants and the refugees will still arrive in large numbers and once settled, send for their families to join them. We will have to accept a lower standard of living as our hospitals, schools, housing stock etc becomes full to saturation point. They will only stop living when our standard of living has fallen to the levels they can get at home.
I think our only chance of flourishing is to leave. If we don't, then we are tied to a union that is committed to the euro, won't get its act together to expand its economies, and insists on being able to put its citizens in our country if they want to come here. It works two ways of course, but a rich pensioner in Spain or France doesn't compare to a minimum rate worker with a family of three.
If we leave, we can use our resources and energies to make our country better whereas inside the EU, anything we will do will be subject to their rules and must be shared with their citizens.