Betting on the stock market (mutual funds) over timescales in decades is about the least risky thing you can do. You don't need a 5% return every year (that won't happen), you just need it to be the average.

There is a difference here because you need to draw on your funds.

The math works out well for someone willing to buy and hold for a long time, because if there's a crash you wait to sell until the market has recovered. However, if you need to sell, you need to actualize the losses. Even if your portfolio later recovers, you've lost out on the growth that you would have had.

Sure, during a crash you have to draw down. But in a 10% growth year, you can get it back. Averages.

There are a thousand and one ways to mitigate risk in terms of choosing investments and withdrawal strategies and your FIRE age, it makes no sense for you to be so negative of the concept. In the extreme case, some people make so much money starting so early that they can live the rest of their lives just on cash.