Of the four biggest US national carriers, T-Mobile is the only one to currently not (officially) carry Apple’s incredibly popular iPhone. There have been countless rumors throughout the years, but today, T-Mobile COO Jim Alling put the majority of them to rest by commenting on the GSM carrier’s lack of one of the world’ most popular handsets.

“Make no mistake about it: We would love to carry the iPhone. However, we want the economies to be right for us,” Ailing said during the Morgan Stanely 12th Annual Technology, Media & Telecoms Conference in Barcelona, Spain. Similar comments were made by COO Tom Keys of MetroPCS, the carrier with which T-Mobile plans to merge sometime in 2013. “It would be harmful to MetroPCS to have to cut out part of our handset portfolio to accommodate one phone from one provider that the economics could be at risk,” Keys said in August.

Ailing notes that T-Mobile understands the lack of an iPhone is likely hurting its ability to gain and retain customers – even going so far as to say that it’s a “point of churn” for the company – but mentions that iPhones are indeed being used on the carrier’s network through the company’s SIM-only Value Plans, which allow some 1.5 million users to operate their iPhones on T-Mobile’s 1900MHz spectrum.

It’s obvious that T-Mobile would love to carry the iPhone, but only if it would mean that the rest of its portfolio would remain untouched. I don’t know exactly how carrying Apple’s device would affect the availability of other T-Mobile handsets, but apparently it would – and that’s exactly why T-Mobile likely won’t be carrying it for quite some time.

[FierceBroadbandWireless]