Earlier quoted context omitted.
With no employer match, a 401k has ZERO tax advantages. Because it merely delays when your income is taxed: after withdrawing it from the 401k. Mathematically you end up with the same capital whether your pay income taxes today and invest post-tax money, or whether you invest in a pre-tax 401k and pay taxes later.
That's not true: the capital gains you accumulate are pre-tax, so your entire investment is taxed once, upon withdrawal, as income. With up-front taxation you still end up paying additional capital gains taxes at the end of the day on your total capital gain. There are conceivable situations where you end up paying more in taxes, if your retirement income tax rate is higher than your current income tax rate plus your…
Hopefully few people will come to need such protections, but that's an additional way to keep it "truly your money".