Nice introduction for those who have never come across open-source software before, although I bet everyone in the engineering community has actually used it whether they know it or not.
A lot of the really heavy-hitting open source stuff started life as a code donation from a big company (e.g. OpenOffice, Eclipse IDE, Netscape) which was then taken and improved beyond recognition. I think it will take a code donation from PTC, Dassault or someone to kickstart a really plausible open CAD project. Say CADDS5 or Catia V4?
I did come across this open source PLM solution which seems to be quite competent if the movie and screenshots are anything to go by. I can't install it here because we prefer to pay lots of money for a proprietary solution ( that seems to be a mostly R&D product ).