They call that collusion.
It's not like they're negotiating to leave off FM chips in some darkened back room underneath a casino somewhere. I'm positive that the phone companies meet with the hardware makers and say, if you want your phones sold on our network, we'll pay you X per phone and we want X features added/disabled. This is visible to the consumer as bloatware. That stuff doesn't get installed at your local store after delivery, it's baked into the ROM and can't be removed without a root-n-flash. If they dictate including apps that aren't stock, you know they must be doing that with hardware as well.
A perfect example of this is the original Galaxy S by Samsung. Although it eventually spawned no less than 10 models in the North American market alone, the original core batch consisted of four different models. Four different models for eight carriers running just
two different technologies. If the carriers had no sway in hardware design, there would have been just two models: The GSM model for AT&T, T-Mobile (and later, Wind); and the CDMA version for Verizon, Sprint, US Cellular and Cellular South (now C Spire).
Instead, we got four unique hardware models. The Captivate was customized for AT&T and Rogers. T-Mobile got a unique version called the Vibrant. Sprint got their own model as the Epic 4G and then Verizon, Cellular South and US Cellular got identical hardware for their Fascinate, Showcase and Mesmerize, respectively.
Guess what — NONE of them match the global original Galaxy S in specs. The original world-spec phone had an FM chip with RDS and a front facing 0.3 MP camera. Both features were deleted for all the US carriers, even though Samsung put out a "global for the Americas" variant called the GT-9000T with those features left in, but it could only be bought unlocked at full price.
T-Mobile is the only one who wanted a front-facing camera and theirs was an upgrade to 1.3 MP (this later showed up on the Galaxy S Infuse on AT&T and Rogers, along with a faster processor and bigger screen.)
The CDMA carriers dictated a different change. Their models had an LED flash for the camera, whereas the others didn't. (Verizon, notably, replaced the default Android search through Google with Bing, which was met with some derision.)
The FM chip deletion was physical in the US bound phones but as I understand it the Canadian phones actually left the chip in and they just weren't turned on; they could be activated with a simple app store download that turned them on, no rooting necessary.
So yes, the phone makers do dictate what hardware goes where, and if that's collusion no one's doing anything about it. It obviously goes beyond the usual band/technology variations that are necessary for each carrier around the world, too.
