I didn’t see the pattern either and had to look it up. Apparently, you can rewrite 1 + 1/(1+2) + 1/(1+2+3)+… as 2(1 - 1/2 + 1/2 - 1/3 +…+1/n - 1/(n + 1)) = 2(1 - 1/(n + 1))

From there, the limit of 2 is obvious, but I guess you just have to build up intuition with infinite sums to see the reformulation.

I think the text tries to make the point that it doesn’t work not because but despite him being black. The argument Perry and others make in this case is not one in the form of material benefits but rather moral ones. A member of a marginalized group makes it big, which is supposed to inspire others from this group. The point is that this form of trickle down economics works just as badly as the “regular” one, which is hardly at all.