Apple did not fix much. It forced their hand on some things, but it’s absolutely still in bed with the carriers in general. Search for “iPhone carrier profiles”

Apple did not fix much. It forced their hand on some things, but it’s absolutely still in bed with the carriers in general. Search for “iPhone carrier profiles” to learn more (and see my other comment on this thread). These carrier profiles are preloaded with the OS (and updates are downloaded on-demand based on SIM ICCID and MCC/MNC) and even apply to phones purchased outright directly from Apple, and used as an anti-competitive way to control access to certain features such as visual voicemail, calls/SMS on Mac (if the carrier profile allows it, your Mac will connect directly to the carrier’s IMS server just like a WiFi-calling client and be able to make calls without having your iPhone nearby) or cellular Apple Watch provisioning. The necessary APIs, docs and access is conditional on signing an agreement with Apple including an NDA.