Even though it’s questionable whether selling smartphones exclusively on one carrier really helps out vendors, many companies keep signing exclusivity deals for their high-end devices anyway. As CNET reports, AT&T has been the master of reeling vendors into exclusivity agreements over the years, highlighted most recently by its snagging of Nokia’s flagship Lumia models and the Moto X’s Moto Maker customization options as exclusives for a limited time.

Why do manufacturers still flock to AT&T for exclusivity agreements even though both Apple and Samsung have shown vendors can have tremendous success releasing their flagship devices across multiple carriers? Largely because smaller vendors don’t have the marketing clout of Apple and Samsung and need to have carriers pitch in to get their devices on the public radar. And because AT&T still has a strong reputation for helping to promote and sell the iPhone, many manufacturers see it as the best bet to help them bolster sales with its considerable marketing budget.

All that said, AT&T’s marketing muscle is no guarantee that a manufacturer will really benefit from it. Let’s recall that HTC decided to sign an exclusivity deal with AT&T for its Facebook-centric HTC First, a device that will no doubt go down as 2013’s biggest tech industry bomb. What’s more, a recent report has claimed that late Apple chief Steve Jobs was apparently so frustrated with having AT&T as the iPhone’s exclusive carrier that he considered breaking off the deal “more than half a dozen times.”