Actually, most world travelers I know prefer to use their own phone number and actually pay roaming costs. But perhaps it's because I'm used to dealing with corporate executives/business travelers, not casual travelers. (I fought this due to the high expenses, but it's hard to tell the CEO he can't have is own phone # when he travels). But I'm betting those business travelers make up a larger portion of traveling users than the casual travelers do.
Being a world traveler myself, I could disagree as well. But of course I'm just one person and I recognize that. Since I was a casual traveler and I didn't have an iPhone at the time, it was just as easy for me to rent a phone than to drop a SIM in a GSM feature phone. More recent trips I just roamed using my iPhone. I didn't have a need to make a lot of calls.
Let's also recognize that a large majority of the iPhones out there are locked. So that pretty much negates this argument in the context of the iPhone.
Oh, and only 83% of the world is using GSM. While Verizon will retire CDMA in about 10 years, it is actually growing in China and India. CDMA is continuing to be developed as well. With those things in mind, it's hard to say it's a lost cause. However, just like the technology standards of GSM (GSM is no longer a technology standard, but an organization) the current technologies of CDMA will be retired.
Oh...and funny thing...the GSM organzation abandoned TDMA to go with W-CDMA....which shares some of the base spread spectrum technologies as CDMA. So yeah....CDMA will die...just as all the previous GSM technologies have as well. It's the evolution of technology. I always find it so funny that people get some sort of satisfaction out of saying "CDMA is dying". I wonder if they did the same for TDMA? Will they do the same for HSDPA when LTE takes over? It's just a wireless technology, they all upgrade over time. Why the fanboyism?