at the top of the pyramid, a cascade of those children

最顶层降生的孩子在很长的时间段中
were forced to be downwardly mobile for a long period of time

要被迫逐渐向社会的下层移动
populating each level of British society with adults

从而使英国社会的各个阶层
who had begun life with the advantages of being on top.

都充斥着拥有上层血统的成年人
It's easy to make up a story, which Clarke does,

故事很好编造正如克拉克做的那样
to the effect that the energetic effort you might expect

来期待这些被挤出上层社会的人
from those people who had been pushed down might increase

能对工作积极度和经济竞争性
the intensity of effort and competition in the economy.

产生积极的正面作用
He then makes a series of gestures towards biological darwinism.

他又提出带有生物达尔文主义色彩的观点
To the effect that Britain led the industrial revolution

之所以英国引领了工业革命的浪潮
because it had a disproportionate number of very able people,

是因为英国有更多有能力的人
and the assumption here is that the rich

这里是假设富人