If you look at Britain since WW2 making a near unerring series of uniquely poor decisions then yes, I think its kind of inevitable we will vote to pull out.
As for why, well its a combination of remarkably stupid right wing politicians who are convinced we are still an Empire, economists who will throw everything under the bus to turn London into the next Singapore, and well meaning people who have the naive faith that everything they read in UK newspapers is copper bottomed fact, rather than honey coated bilge from the Murdoch Pravda.
Not that the EU has done a particularly great job at welcoming the UK to the EU. In fact you can trace much of the present problem down the self serving prick De Gaulle. It took, what, 15 years to get into the EU? Look at the haste everyone fell over themselves to get Greece in.
We initially refused to get involved. We didn't need no steenking continentals! We didn't even attend the meetings that set up the ECSC, despite being invited, & withdrew from the Messina Conference. When the EEC was formed despite our refusal to participate, we tried setting up an alternative, EFTA - but it was damned feeble compared to the EEC. We bit the bullet after a few years & applied to join, but while we'd been dismissing it & trying to disrupt things de Gaulle had happened, & he didn't want any interference with the nice tidy arrangement he had with West Germany to run the thing.He may also have suspected that our intention was to be a spoiler, after our previous behaviour.
From when we first applied to when we joined was 10 years. Before that we'd spent 12 years alternating between ignoring moves towards economic co-operation in Europe & being disruptive.
If we'd been in from the start we might have been able to get some improvements, e.g. in the CAP, but by the time of Macmillan's volte-face that was all done & dusted & it was take it or leave it.
In actual fact we seem to be slap bang between our 2 dates, this states Macmillan applied in 1961, and we got in in 1973, so thats 12 years. Which still seems remarkably tardy, even allowing for Labour not wanting to join, and De Gaulle being an obstructionist prick.
And yes, we didnt want to join initially. I think Churchill was one of those who advocated a prototype common market, but didnt believe we should be part of it. That was a major mistake. One only has to look at NATO which we joined on the ground floor and one can see that it is much more akin to what we want and like.
But thats by the by. Doesnt it imply that the EU (and I argue we ought to remain part of it) is wholly unable to depart from those founding values established by West Germany and France and the other founding members? We might be a part of the reason for that in our desire for splendid isolation then and now, but that it still is arguably true that the core of the EU make all the major decisions and the rest to a large extent put up with them is still evidently true. Did we get much chance to mould the events of 1992? Because it certainly didnt look like it at the time.
That probably comes across at Eurosceptic, and I probably am. I still think we would be soft in the head to leave.