I genuinely don't understand your point with the graph. Do you think that those companies only operate in the country/continent they originate from? Besides that, the graph just shows growth in Asia at the cost of the US market.
Not that any of that will change post-Brexit anyway, they'll still need to comply with EU regulations and there are still cheaper places to operate from than the UK.
But obviously muh oppressive EU overlords stop me accessing Google, I'll be so grateful to leave the EU and have more personal data stripped.