It must be said that the most recent Samsung Galaxy S4 does have a locked bootloader on both AT&T and Verizon, although the Galaxy S3 did not happen to fall under a similar fate over at AT&T. Concerning the Moto X’s bootloader status, AT&T mentioned that they will not support unlocked bootloaders in order to ensure a “safe and consistent experience on your wireless device”. I guess this would mean all future handsets, too. Of course, the homebrew club will most probably be able to find a way around this, as there would still be a fair number of people who would want to install custom ROMs on their respective devices, and an unlocked bootloader is the way to go.
Do bear in mind, however, when you unlock your phone’s bootloader, its warranty will become void, not to mention your handset’s internal memory including applications, contacts, SMS and MMS messages will be wiped clean.