The case very nearly didn't go forward in the first place. An appeals court effectively tossed the lawsuit in 2016 on the grounds that AT&T's common carrier status exempted it from disclosing its throttling activity. In 2018, however, a federal court decided that the FTC could proceed with the case after noting that AT&T's data services weren't part of its common carrier status.
The lawsuit alleged that AT&T misled legacy unlimited data customers about its throttling plan, failing to adequately inform them that they'd see dramatic slowdowns after using a certain amount of data each month. This wasn't really the unlimited service they'd signed up for, the FTC argued. AT&T balked at the lawsuit, arguing that few people were affected and that it notified customers of imminent throttling through text.
There's no doubt that the wireless landscape has changed a lot since the lawsuit began. Like it or not, throttling is a staple of many US carriers (including Engadget parent Verizon), whether it's after a given amount of general usage or for specific services like video. A settlement might not carry much weight unless it forces substantial changes to existing disclosure practices.