Once you start selling off your assets, the """returns""" are worse, but equally so no matter what you invested in. It's better to leave that math out of the situation and look at the returns of the actual assets by themselves. Which includes reinvesting.

If you really want to factor in the sell-off, then every dollar of dividend means one less dollar of sold stock. If dividends go higher than withdrawals for a year, then you need to buy more stock to compensate. So the math comes out the same. What you don't do is ignore dividends, or let excess dividends pile up in cash form. Which the original paper apparently did.