I don't think it is entirely coincidental, though probably much of it would have happened anyway, due to the productivity gains delivered by technology, from the 1980s to 2000s, and then even more dramatically from the arrival of the mass internet, and connected world. Not only are we able to conduct this type of forum :-), but the growth in the global market through instant communication, transactions and trade has had a massive impact on business, and of course on lifestyles. The smartphone and apps have created huge new businesses, sometimes reaching $B valuations within MONTHs, and these businesses have very little respect for - or need for - borders. Order an iPhone from Apple's online store in France, and you will be buying a US-designed product from an Irish company, which likely ships direct from China, where it was assembled a day or so previously from components sourced from 20 - 30 other countries. Try doing that in 1980.
So to while we can argue about the economics (actually I think it is a clear win for Remain), the decision should really focus on the reality of the connected world we live in (not an idealised 1950s version, which is gone).
This means we need democracies to be able to control these tech behemoths. So if Google abuses its monopoly to favour its own sellers, it must be slapped down. If Facebook adds bias (human or algorithmic) to News Feeds, our elected institutions need to have the muscle to react. The tax system is broken for multinationals: paying corporation tax against profits allows companies to choose where they pay - Apple pays about 26% corporation tax overall, but not much of this is in Europe. This needs addressing. Google and Facebook have no physical products, so they have even more choice as to where to pay.
Anyone who feels that the UK alone is able to tackle these is living in the past.
This is why localism is a backward-looking and simplistic viewpoint that will inevitably flounder on the rocks of today's connected reality. "Take back control ?" And how exactly would the UK alone be able to counter the might of Google, Facebook, Apple etc? Or address the other major global - even existential - challenges we face: pandemics, mass migration, cyber and financial security.
We have a Brit up there, sitting in a (multinational) tin can, watching the world go by - Tim Peake sees no borders. Borders are a human construct, largely of the 20th century (no passports were necessary for international travel before 1910, I believe). And didn't the 20th century turn out well! Borders ---> Nationalism ---> Wars - only religion has caused more wars over the centuries.
So come on humans, let's try to think a little bigger. We live on a small planet, and if we insist on fragmenting ourselves to "take back control" of our little fiefdoms, there will be no human 22nd century.