The linked article actually talks about a scenario in which the retiree experiences a drop in market value right off the bat, when taking a fixed figure (adjusting upward for inflation every year). It’s initially based on a percentage of the value at the beginning of things - e.g. the person takes 4% of a 1M nest egg. Then that 40,000 bumps up the following year - if inflation is 5%, she takes 40K x 1.05. or 42,000 in year 2, and so on.
Going with that approach, any bad year can have a permanent effect on your funds. SO yeah, your nest egg WILL shrink if the timing happens to be bad.
Another approach I’d heard is to take that percentage each year. If her funds perform well in the first year, she’s got a larger basis to take the 4% from. If they do badly, she has to either get less money the next year, or she takes a larger percentage of the value.
e.g. if her 1M drops to 920K after year one (between the 40K wothdrawal, and losses), the next year she either takes 36,800 the second year, or she takes a larger percentage of the 920K. 40,000 is 4.3% of the balance.
Taking a fixed PERCENTAGE of your funds may mean income variation from year to year but won’t chisel away at the priincipal as fast.
If you are lucky / frugal / etc., you’ll hopefully be able to live even within the 40K (plus other sources of income like SS, pensions) and put a little of that aside to cover the shortfall in year 2. and so on. And the amount you don’t use in year 1 may be gone from your retirement account, but you can still save / invest it in non-retirement funds.
An alternate approach is