The picture changes again on even longer time frames. Stock growth rates have been remarkably consistent over the past couple hundred years. Even the Great Depression is barely visible when you look at the largest sample we have. (Although, obviously one must discount a little for Keynes' objection about the long run.)

Most people didn’t have a timeframe of 100 years. More likely something like 30 or less. If there is a downturn during that time and you don’t have enough cash to avoid touching your principal you can quickly have a problem. For example let’s say stocks have a downturn and you have a serious health issue it’s very possible that all your proceeds are gone and you don’t have any money to reinvest when the market goes up.

> That’s the view of people who have grown up during an ever rising market like the last 12 years and think that’s just the way it always is.

No, which number is the right pcomparison to be apples to oranges before considering risk has nothing to do with that.

Interest rate on debt is directly most comparable to nominal return on investment, not real return.

I haven't discussed at all what the correct risk premium to assign to stock market investment based on its historical volatility and what interest rate that would suggest is appropriate to consider equivalent on a risk-adjusted basis, either for some presumed generic investor (which would be meaningless in concrete terms) or in any concrete investment scenarios.