Comparing the 1/4"-20 tripod mount to the 1/8" TRRS jack isn't a great comparison.
The tripod mount has been a standard for decades and decades.
The phone headphone jack fractured into competing standards years ago. Works fine for listening, but once you want to use a microphone you're dealing with different pinouts for different manufacturers, balkanized auto detection and signaling, incompatible plugs sizing, grounding issues with the phone case, etc. It wasn't a pristine situation when Apple left it behind.