It doesn't come up because the US mobile phone market is almost completely balkanized: how many handsets are released in GSM and CDMA versions (or even that do both GSM and CDMA)? Hardly any.
Buying a cell phone in the US basically means picking a carrier and then picking a handset. In almost every other country--and certainly those that are GSM based (including all of Europe and Australia)--have handsets that are interchangeable on networks.
Why there aren't cross-technology phones (barring some minor exceptions) is exactly why Apple won't do it either. Particularly because CDMA is a dying technology anyway (at least in the developed world).
But people change carriers a fair bit. Churn is huge in the US. And yet almost no one picks one carrier over another due to this feature. The big CDMA carrier is bigger than the big GSM carrier. And the little CDMA carrier (Sprint) is bigger than the little GSM carrier (TMo). It's really a non-issue.
And even the Samsung Galaxy S phones... read the reviews. While people talk about some differences on the phones, I haven't seen a single review mention the voice/data issue. And they just announced selling 5 million units in just a few months -- so its not exactly a niche phone.
And a quick search brings up a ton of "Android Fragmentation" issues. They talk about everything from 1.4 vs 2.2. of Android to screen resolutions to keyboard/no keyboard to camera support, etc... I haven't found a mention of voice/data fragmentation.
So if this is a problem that Apple would have it would be one that no one else in the industry has had to explain. I fully expect Apple's magic would make this the same non-issue it is for everyone else.
My point is that I don't think the following conversation happened:
CFO: "Hmm... we get an extra $30B in profit if we support Verizon, and effectively end Androids short run and block WP7 from ever breathing.."
Jobs: "Screw it. This will mean that some customers will have voice/data and some won't. And while our current users can't touch their phone and make a call at the same time, and the fact that we're selling a neutered product in AppleTV, this is where I draw the line. Even if it means that we completely dominate the mobile space for here to eternity. I draw the line here."
I just don't think it happened at Apple or at "most companies".
Buying a cell phone in the US basically means picking a carrier and then picking a handset. In almost every other country--and certainly those that are GSM based (including all of Europe and Australia)--have handsets that are interchangeable on networks.
Why there aren't cross-technology phones (barring some minor exceptions) is exactly why Apple won't do it either. Particularly because CDMA is a dying technology anyway (at least in the developed world).