This does not negate the original post, but $10,000 invested in the S&P 500 on Jan 22, 2009 would be $20,038.80 today. (According to morningstar.com; note that this is "total return" with dividends reinvested. They get both this and mutual funds (where distributions are reinvested) correct. Google Finance does not do this.)
With a market this volatile and divorced from reality you can pick a timeframe to make any point whatsoever. No human or algorithm can reliably call these things.
Today's post, Investing for the Long Slump was originally published on 22 January 2009. A summary (taken from the LW wiki):
Discuss the post here (rather than in the comments to the original post).
This post is part of the Rerunning the Sequences series, where we'll be going through Eliezer Yudkowsky's old posts in order so that people who are interested can (re-)read and discuss them. The previous post was Failed Utopia #4-2, and you can use the sequence_reruns tag or rss feed to follow the rest of the series.
Sequence reruns are a community-driven effort. You can participate by re-reading the sequence post, discussing it here, posting the next day's sequence reruns post, or summarizing forthcoming articles on the wiki. Go here for more details, or to have meta discussions about the Rerunning the Sequences series.