One thing that separates the US and UK is not only size, but coherence. Something which youth culture can teach us.
It's entirely possible - nay normal for a fad to start in the UK in (say) Cornwall, and be in John O'Groats a week later. And then just as quickly burn itself out. This is why when MTV started up, it was playing UK artists that were already well past their UK sell by date. Although it did help them break the states.
I wonder if the same applies to culture more generally ?
Even within Europe, dealing with time zones isn't really a thing. Whereas if you live in NY and need to deal face to face with someone in CA, you really need to time it carefully. That physical (and temporal) separation is alien to a UK where we all sit down at 3pm on Christmas Day in hushed reverence to hear the wisdom of our anointed sovereign with the only distraction coming from trying to hold a fart of nuclear proportions in until the room is clear.