The real reason most source is closed? Open is hard
The Register - Matt Asay - Open...and Shut As much as 95 percent of the world's software is written for internal, enterprise use, rather than by vendors for sale, a point famously made by Eric Raymond in The Cathedral and the Bazaar. Much of this software, in turn, has no proprietary value for the enterprises that develop it. So why isn't the world deluged with enterprise-written open-source software? Why do so many CIOs gladly use open source but not contribute to it?
Because open source is hard. Really, really hard.