Earlier quoted context omitted.
You think the stock market will be around when you are old enough to need your 401k? I max my contributions but I have no faith they won't be wiped out in some future crash.
You buy shares in the stock market, not dollars, so a crash shouldn't hamper your ability to retire, unless you want to retire during the crash itself (although diversity of assets would help with this). The stock market recovered years ago from the Great Depression and is doing really well again.
We are already to the point where there's so much private equity that startups don't need IPOs. So it's entirely possible that the next Google, Facebook, Amazon, Apple and Microsoft will never be exchanged on open markets.