4G GSM and 4G CDMA are the same thing, LTE.

But, IMHO, CDMA carriers are still going to be behind GSM, because too many of the CDMA conventions used when implementing CDMA-based networks are based on American mentality (the "who cares about the rest of the world, we don't go to Europe"), which has resulted in the lack of things like standardised roaming between CDMA operators and many other related issues.

Ignoring the "4G" bit, it is quite a bit more expensive to produce a dual-technology (CDMA and GSM) phones, due to royalties and additional radios, chipsets etc. Especially for Nokia, since they don't pay much in royalties for GSM. About the only people who actually need dual-technology phones are CDMA carriers, to provide their customers with roaming ... see above.

Of course, I wonder why the Symbian issue is always the one brought up when discussing Nokia's US market share (e.g. vs Android), when a bigger issue (IMHO) is that they only make phones for half (or less, considering the US-specific 3g frequencies) of the US market. Maybe Elop should have considered actually playing in the other half of the US market.