> This wasn't real world behavior, and FreeBSD using the GPL wouldn't have forced Apple to give them their DE. A program, say a DE, on a GPL operating system do

> This wasn't real world behavior, and FreeBSD using the GPL wouldn't have forced Apple to give them their DE. A program, say a DE, on a GPL operating system does not need to be distributed under an open source license. Depends on how the DE integrates with the other components. Real-world behaviour: the ecosystem that has a GPL-licensed kernel has much wider adoption that the ecosystem which uses primarily BSD licences. I know this isn't fully attributable to licensing, since the BSDs were afflicted with legal issues during the time when Linux was taking off, which surely contributed to the situation, but still the BSD licences encourage certain types of entities to take without contributing back the ecosystem. Though I admire the idealism of BSD-type licences.