Here's the chart without gold:

Here's the chart with gold:

The above charts are for the time period of 1970 to 2016, so 47 years of data (some of which is synthetic).
Without gold, during the worst 10-year period, you would have had to contribute 3% per year to keep from losing principal, whereas with gold in your portfolio you could still withdraw 3% per year during the worst 10-year period and still not lose principal. Long-term withdrawal rates without losing principal are about 3% without gold and 4% with gold.
When I look at results like this, I just can't understand how people over at Bogleheads and other places can say that gold has no significant place in an investment portfolio. Can somebody play devil's advocate and try to explain it for me?