I think you're incorrect, although I hope you're not.

This idea will never become a reality for the vast majority of companies, for the exact same reason that companies fear piracy. If I open source my product then anyone who uses that open source code is a lost sale. A lost sale means I make less money, less money means the board is mad, on and on and on...

The bottom line is money, and open sourcing their code means (to them) a loss in potential revenue.