PC World has an article on why USB-C has not been a viable alternative for the 3.5mm audio jack. Problems with USB-C include variable handling of digital to audio conversion, incompatible SOCs inside the cable, and non-standard analog-passthrough. In short, the cables which contain computers themselves are not standardized in behavior and the author's conclusion is that mobile devices must have 3.5mm jacks until the USB-C cable technology gets sorted out enough that they become usable.
(Score: 2) by richtopia on Wednesday September 12 2018, @03:27PM
I suspect the headphone jack is more of a cost/size issue. With the entire phone nearing 5mm thickness the 3.5mm headphone jack is quite large. Additionally accommodating it in the board layout, and rating the port for dust/water tolerance are calories that could be saved. I do not plan on purchasing a phone without a 3.5mm jack but I can understand why the industry would like to migrate away from a connector designed for transistor radios of the 1950s.