Most non-trivial manufactured devices contain microprocessors that run software to which users will never get access. For many devices and the vast majority of users, this isn't a problem. Hackers will often want to reprogram the gadgets they buy, and the Free Software Foundation will wonder whether any of this firmware contains code covered by their General Public License, which mandates user access to the software, but the manufacturers don't usually have to think about any of this.
However, there are many small software companies trying (with limited success) to build businesses around the need for tools and components for developing that firmware. The market isn't big enough to be interesting to Microsoft, unless we're talking about mass-market software-intensive devices like cell phones and PDAs, which can use Windows-derived operating systems. The little companies serving this market find themselves increasingly dependent upon leveraging available open-source software - but to the extent that they depend on software licensed under the GPL, they must avoid having to give away their "added value" while not paying programmers to re-implement code that would otherwise be freely available. If they instead use software developed under BSD/Apache-style licenses, they have free and unrestricted use of any code they can find - but they find no code developed for their applications by their competitors, since any who might have developed what they now need were also free to keep their work secret.
Still, to the extent that patents stay out of the picture, companies in the real-time Linux business continue to bring at least some of their work to the public, and universities and government agencies sometimes release real-time software under licenses more liberal than the GPL.
