David Feinleib at Mohr Davidow Ventures has today's great post up titled Why Startups Fail.  Given all the consumer web stuff that got funded between 2004 and 2006, we are heading for another wave of failure as companies run out of gas after their Series B / Series C rounds and their investors lose patience with them.  In addition, you've got the natural cycle of "well - it never really worked" - such as evidenced by the rumor from VentureBeat that Akimbo has thrown in the towel after raising $47m.