Because of how complicated Hard-Drives really are they have strict limitations on how inexpensive they become. I suspect at this point in time the price difference for Sony to include a 80GB hard-drive over a 60GB hard-drive was tiny whereas to jump to 120GB (or 180GB) would have cost a lot more.
If some of the theories are correct, Sony may have reduced the price of the 60GB model because they have 4 to 6 Million unsold 60GB PS3 systems and they are currently producing 80GB systems; this would imply that they are trying to (rapidly) sell off unsold inventory in order to make room for their larger model.







