> The US has easy economies of scale for many types of business due to its large population. If you come up with a successful business model in one state, there is a low barrier to expanding it.

The UK had access to such a market and was quite a large force in certain sectors like finance but then decided to just burn all bridges.

Of course the challenge in the EU is a big higher because of different languages and possibly different cultural attitudes but the UK is now learning how much harder things were back in the good old days.