It really should come as no surprise that Sprint, T-Mobile and Verizon have no love for Microsoft and Windows Phone since they are all part of the OHA with the parent company being Google. (Verizon was sucked in as Vodafone which is a member of OHA owned 45% of Verizon Wireless' stock until September 2013) With that being the case, they will naturally push the product/operating system of the parent company that they are part of. Therefore all other OS sold by them will get second or third class citizen treatment and pushed to the side. Microsoft has said all Windows phone 8.x devices will receive denim, but until they can either directly release the updates and bypass the carrier or they actively work with the carriers, any further updates from the aforementioned service carriers are more than likely DOA.
This is unjust because the carriers (as well as the developer community) are playing a role (albeit marginal) on bringing down Microsoft/Windows Phone's value and credence. You want better quality apps, visit one of the big two. You want better support from the party vendors, go Apple or Android. I am in no way bashing Windows Phone as I have been with the platform since day one, but one has to step back and take off the rose colored glasses and see things for what they are. Until Microsoft goes thermonuclear on US carriers, marketing and advertising, and the developer community, they'll still be trying to play catchup as the distant third OS option. And until that happens those of us on any other carrier other than AT&T, we're fresh out of luck and can/should expect to hear that our beloved devices are EOL and will no longer receive sorry from them.