Let's face it, the run of the mill company that has no real unix sysadmin staff, is scared of Linux.
Not just slightly uncomfortable, because it's something new, ya know, from the 90's, that they don't know, deep seated, instinctual fear as if it's a great white shark about to come up from the murky depths and bite them in half like a scene from 'Jaws'.
The really funny part? Linux is *everywhere*. Want something to run on an embedded device? Who doesn't like Linux? There's a sprinkling of vxworks here and there if you really need a commercial real-time OS, but in reality, 99% of the black boxes out there are Linux based.
Linux is The Truth, The Light, and The Way.