The Mass scene sort of fizzled in the 90s for various reasons - not dead, but not dominant - and the centre of gravity moved to the West Coast.
So if you were born in CA and studied there - and Atkinson did both - your odds of hitching your wagon to a success story were higher than if you were born in Montana or Dublin.
This is sold as a major efficiency of US capitalism, but in fact it's a major inefficiency because it's a severe physical and cultural constraint on opportunity. It's not that other places lack talented people, it's that the networks are highly localised, the culture is very standardised - far less creative than it used to be, and still pretends to be - and diverse ideas and talent are wasted on an industrial scale.