Specs say both CDMA, and GSM capable. 4s

just cause you were schooled no reason to cry.

So, short version is--iPhone 4S, purchased through AT&T, now unlocked → is the device now capable of being activated for either GSM or CDMA? If not, why isn't it and what is the purpose of having it unlocked?

And for the long version →

Since the iPhone 4S is shipped with the capability of being either GSM or CDMA, will the carrier unlock return the device to that status? I have a 4S that was purchased through AT&T online. I used the phone for a year with AT&T until I was given an iPhone 5 as a gift. I am now using the 5 and AT&T has unlocked the 4S. A friend of mine who is a Sprint customer wants my 4S, however Sprint told him that they can not activate any devices that are not Sprint devices. I spent some time chatting online with two different Sprint representatives today, both of which gave me different responses and ultimately were unable to explain to me why Sprint can't activate devices that were not purchased through Sprint or labeled as "Sprint devices". The take home message I got from them was that there is no difference in an iPhone that is capable of Sprint service or AT&T service, they are the same device, my 4S is compatible with CDMA, their network is CDMA, but they can't activate my 4S because it isn't a Sprint phone. I told them that there is no such thing as a Sprint iPhone, the iPhone is an Apple product, not a Sprint product. I told them the phone has no specified carrier information. They told me that means it isn't a Sprint phone and they can not activate it. In trying to get my point across, I asked them if a person were to purchase an iPhone from the Apple store that is not activated by any carrier and bring it to a Sprint store could Sprint activate the phone. The answer I received was "you would need to trade the phone for a Sprint iPhone and have that activated". I think the Sprint people I spoke with online are lacking an understanding of the iPhone altogether as well as lacking the knowledge base to provide answers to the questions I had and instead of finding the correct answers they just told me what they thought they could say to land a sale. Either way, I don't think the answers I got from them are accurate, and if they are accurate in saying that Sprint can not activate a device that was not purchased through them, why is that? It is my understanding that the 4S is capable of either network, the carrier activates the phone and the network info is set at that time and I assumed that unlocking it would restore the original capability of being activated on either network.

So, short version is--iPhone 4S, purchased through AT&T, now unlocked → is the device now capable of being activated for either GSM or CDMA? If not, why isn't it and what is the purpose of having it unlocked?

In theory it could be used with CDMA, but no CDMA carrier in the US (neither of them) will activate a phone that wasn't originally sold for use on that carrier's network.

Do you know why they won't do it? I can't get a straight answer out of Sprint

Because that's their policy.