Yes Pareto's distribution is supprisingly accurate but this:
Life Is 20% What Happens To You And 80% How You Respond
is a massive stretch.
Pareto principle states that 20% of input produces 80% of the results. I don't see how is it relevant here (or to JK Rawling/S Jobs mentionings).
It's not supposed to be data driven. Just take it in an abstract way :)