XServe is really not much of an indicator, since it's always been a pretty poor seller. Apple never did figure out why the likes of Dell and RackSaver rack-mount server solutions cost 2-4x as much as Apple's, and why everyone else kept buying them instead of Apple's far cheaper solutions -- and therefore Apple never fixed their big problem.

You don't pay a premium in that market for nothing -- your rack-mount server has a CPU go up in smoke, and Dell WILL have someone in your datacenter replacing it within 24 hours. That's the part that Apple didn't get -- shipping your box back to the manufacturer just doesn't cut it.