I know people that still run OpenSuSE 11.2 on their internal systems. No amount of "open source" will have customers modify what they see as a working system, especially not when any upgrade comes with a week of integration followed by tests and bugfixes to ensure flawless operation in production. The difference between OpenSource and Proprietary is in this case that Windows XP exists and works well enough while GNU/Hurd doesn't and therefore will never have an outdated version in use.