Its because most of the world uses GSM. America is weird, having different carriers use different bands, frequencies, and being split in the middle with 2 technologies. CDMA, I believe, is able to be spread out farther, with fewer towers in between from my understanding, explaining Verizon's signal (What, you thought they were better because they had more towers?), but its also a more expensive technology, as far as I understand. GSM is more common in the rest of the world.
Originally Posted by mrmdj31675
Basically, if Microsoft is focusing more on GSM, its because that's where most of the world is. Granted they could boost their User % in the US by putting more focus on CDMA, but that would require them to focus less on GSM, thus hurting their user % in most of the world (which in some countries they have up towards 30% user share).
Though, Microsoft isn't the one doing this. Microsoft programmed Windows Phone, but that has nothing to do with CDMA or GSM. That's a firmware thing, which falls to OEMs. Meaning Nokia and the likes are focusing less on CDMA. Though my explanation still stands. Just replace "Microsoft" with your WP OEM of choice.
Here is more explanation on gsm vs cdma: Giz Explains: What's the Difference between GSM and CDMA?
CDMA is and has been basically trying to remove GSM (global standard for mobile communications) and its successors from the throne for years, ever since it came out, and its so big in the US due to the advantages it once had over GSM (but is no longer relevant with gsm's successor's technology.). Now days, CDMA doesn't have much advantage anymore (except in rural, less advanced communities that are a bit behind in the world), but it has such a foothold from those early days that its hard to get rid of that easily.
Also, Lumia 620 is on Aio. around $200 I believe.