Well that quote is talking about iPhone bussiness everywhere, and since Apple only has their iPhone exclusive in 3 big markets(US, Germany and Spain), that quote could be talking about spreading carriers in markets where they already have many different partners.
I'm not saying Apple isn't planning non-AT&T iPhones in the US for Sprint, Verizon and T Mobile, I'm just saying this quote isn't any solid piece of info to say they.
I don't know much about the cell phone market in Spain and Germany, but I know in the US, the differences between all their carriers means many different models of the same phone, which is reason to keep one carrier(now I think there are more reason that would make financial sense for Apple to release a CDMA phone, so hardware which supports Verizon and Sprint are the same...sadly T Mobile wold require its own device to support its 3G network, and considering how few people use that standard, I'd say its the least likely, but I can hope.