Vista Starter - No DVD codec
Vista Home Basic - No DVD codec
Vista Home Premium - DVD codec included
Vista Business - No DVD codec
Vista Enterprise - No DVD codec
Vista Ultimate - DVD codec included
So that's 4 SKUs without a DVD codec and 2 with. Unless Math changed last I looked 4 is bigger than 2, so most Vista SKUs shipped without DVD codecs. Do you understand yet? Do I need to use shorter words?
Actually Microsoft DID provide DVD codecs for Vista Starter, Home Basic and Business if the OEM licensed it that way. So Vista would have played DVDs out of the box for almost all home users.
OEMs (PC manufacturers) had the option to license Windows Vista Starter, Home Basic, and Business "with DVD" where we offered a version that includes the Dolby Digital codec to enable the OS to support DVD playback for a nominal price increase.
Why they can't do this for Win 8 is beyond me.
wrt. enterprise: If you're in an enterprise and you need to play DVDs your IT department should already have ensured you have the correct software/hardware. (Not saying that giving the IT guys extra work to do is a good thing, or that this is an ideal situation, but that it shouldn't impact the end user.)