Whidrawal rates are a simplification the same as growth rates. They should not be expected to be constant. Withdrawals tend to be absolute (with some flexibility like not taking a trip or not renovating a kitchen or deck) rather than relative to market gains. Also withdrawals can be made in a way that changes your asset allocation (don't sell your equities in a downswing, sell your fixed income assets for needed liquidity)
All that said, I'm going to read the article now and see if they hit on any of those points.
PS Dave Ramsey is who idiots think is smart, so I pretty much disregard what he says as he says it.
