Some do. Some don't.
And I've had some success running them with dosemu. I've tasked one of my techs with running through they myriad of DOS applications on both dosemu and dosbox (we have one lone OSX box here, but we may be replacing our 'doze notebooks with iBooks next year - IF we can run the required DOS apps with dosbox).
I still have approximately 35 MS-DOS workstations running in production. I try not to think about that much. ;0(
Edit: As for the printers, we have one version of an OEM driver that does work with XP.
