Very good point: it should say "the British ran their island .... into the ground". 

By the early 1970s, Britain was broke, broken and needing the IMF to bail them out. Since joining the EU, Britain has enjoyed continued economic growth and improvement. Much of this has been using European brains and labour and wealth. There is no Empire coming back. Britain had the worst levels of poverty in Europe for centuries and still lags on most indicators in Europe, but has improved greatly from where it was. 

The people who voted 'Brexit' tend to be the laziest and most ignorant in the population. You can be damn sure they will not be the go-go thrusting people embracing the global economy and all its people. Post Brexit, they will, I am sure, sink back into their shabby, damp, moldy hobbit holes and gripe and moan about the world while waiting for their bennies to come through the post.