You need to briefly summarize so readers can decide whether to read.
The article basically complains that sophisticated modern retirement calculators are better than old assumptions that used a single rate of return. But despite monte carlo runs, and historical scenarios, the calculators still tend to return a single result at a chosen success rate - say 90%. Better would be to return results at several success rates (e.g., 100%, 95%, 90%, 75%, 50%, 25% in his example) to provide more comprehensive information. No big news to erdotorg denizens.
Every man is, or hopes to be, an Idler. -- Samuel Johnson