There's nothing illegal about creating exclusive deals or trying to compete in ways that might not be the best for customers, but doesn't rise to the level of anti-trust. That doesn't mean it doesn't seem bad, but there's a difference between kinda plain-old "I wish they'd give me a better deal" and anti-trust.

Apple's exclusivity with AT&T didn't create a situation where AT&T could crush competitors. That's ultimately the crux. Qualcomm's dealings had been working to eliminate competition in the LTE modem space until Apple started working with Intel. You couldn't get an iPhone on Verizon, but Verizon was still signing up millions of customers without it. It certainly helped AT&T, but it didn't create a market where competition was eliminated or endangered. As Android phones came along, they were a drop-in substitute that other carriers could use. Sure, you might want an iPhone on Verizon rather than Android phone on Verizon, but that falls into the "I want my perfect deal" rather than something really endangering competition. It's clear Verizon would continue to be a successful company offering competition even without the iPhone.

Qualcomm was the only company offering high end modems. Companies might buy modems from Intel or others if they made high-end modems, but Intel isn't going to make a high-end modem if no one is going to buy it. By requiring exclusivity, Qualcomm made it so that there weren't enough customers to support an alternative high-end modem.

To come up with a hypothetical iPhone scenario, let's say that Apple launched the iPhone in 2007 on all networks and required AT&T, Verizon, Sprint, and T-Mobile to commit that they would only sell iPhones and no competing smartphones. Google might invest in Android, but there'd be no one to buy the devices. Sure, a few people would buy them outside of the carriers, but there wouldn't be enough demand to be profitable, Google would invest less and less (maybe even shut it down) while Apple poured money into iPhone R&D. A few years later, Android would be gone.

Apple's exclusivity with AT&T actually helped competition. Verizon wouldn't have promoted Android heavily if they had access to the iPhone. People would have bought iPhones 2007-2008. Instead, they often bought Android devices because they were on Verizon or Sprint or T-Mobile and that's all that was available. Apple's exclusivity helped Android gain a foothold. It wasn't until 2011 that the iPhone launched on Verizon and that 3.5 year period gave Android the time it needed to flourish.

Sure, Apple's move wasn't consumer-friendly. However, if anything, it helped competition. Regulators aren't about making sure that everything is the most consumer-friendly. They're about making sure that you aren't stifling competition. Apple's exclusivity didn't harm wireless competition: Verizon was still doing well over that 3.5 year period. Apple's exclusivity, if anything, helped competition in the smartphone OS/device market. As such, there wasn't a problem that needed correcting.

If Apple had launched on all the carriers and required them to exclude Android devices from their lineups, that would have driven out competition. Qualcomm is accused of seeking exclusivity to prevent companies like Intel from producing high-end modems. If all the customers have an exclusivity agreement with Qualcomm, no one would buy Intel's modems. If all the networks had exclusivity agreements with Apple, there'd be no one to buy Android phones.

Apple's exclusivity is more like the exclusivity of Orange is the New Black on Netflix. Maybe I don't want to pay for Netflix to get one show. Maybe I don't want to join AT&T just to get an iPhone. But as long as there's lots of competition and you can replace Orange is the New Black with The Handmaid's Tale on Hulu, there's robust competition, no one's getting driven out of business, etc. Netflix is gaining customers and Comcast might be losing customers, but that's "fair" - or at least fair enough for regulators to ignore it. Comcast can make better exclusive content on NBC, USA Network, Syfy, and Bravo or license it to regain customers. Verizon did push hard for Android devices like the original Motorola Droid to overcome their lack of iPhone.

Again, exclusivity deals might not be great, but anti-trust law concerns itself with companies that are using a dominant, monopolistic position to eliminate competition.