Definitely a lot of valid points - but it still comes down to people trying to time the market.

Most people will build their portfolio over time meaning that few of their purchase will be at the bottom or the top of the market.  Those that stick to their investment objectives during turbulent or effervescent times and thus avoid the stereotypical buy high sell low scenario will rarely succumb to the dangers suggested.

Larry references Warren Buffett a few times to prove or illustrate his point.  One should note however, that Warren Buffett is long term buy and hold type investor - as per another infamous quote "our favorite holding period is forever".

Some people will take this article to champion their "the end is near" campaigns and certainly at some point in the future there will inevitably be a correction or crash.  The ability to predict the timing of the events listed in Catou's Wikipedia link without being spotted a year or two or three is far less certain.