It was the age of zeroes, the epoch of naughts, an era when we started with something and added just about nothing.

At least that’s what stock market commentators have been gravely telling us for at least a year. The 2000s, they argue, was a lost decade. And at first glance, they appear to have gotten it exactly right.

If you invested $100,000 on Jan. 1, 2000, in the Vanguard index fund that tracks the Standard & Poor’s 500, you would have ended up with $89,072 by mid-December of 2009. Adjust that for inflation by putting it in January 2000 dollars and you’re left with $69,114.

But that is not how most real people invest. They don’t pour everything they have into just one type of asset and then add nothing to it for 10 years. Instead, they buy stocks of all sorts, and bonds and perhaps other things, too. And many millions of them dutifully add more money regularly, usually into a retirement account that they won’t touch for longer than a decade.