Although 475AD is the year that shows the 'decline' of the Roman Empire, it is not the year of its 'fall'.

But it's the rhetoric of failure.

The decline can be traced to the 1950s.

Two great civilizations slowly fell into decay.

If we continue like this, it's as clear as day that the Japan of five years on will be in decline.

Briefly stated, Hobsbawm's thesis is that the history of the twentieth century is that of the decline of civilization.