I wouldn't say the US is far ahead. According to Wikipedia, the US is at fourth place by purchasing power parity, with a PPP adjusted per capita income of $43223. The UK is at the 13th place, with a PPP adjusted per capita of income of $35486. Luxembourg is in first place, with a PPP adjusted per capita of income of $81511. Now that's far ahead!![]()
Luxembourg is obviously a (small) special case. That's 18% difference between the US and UK. That's a large amount. Under realistic circumstances, say 4% growth in the UK and 3% in the US, that'd take about 15 years to close the gap.