Because that doesn't work on the iPhone. iOS has those settings baked in.
I ditched my iPhone when I got tired of my tethering options randomly disappearing/reappearing on minor iOS updates without a chance to override that. Even though my carrier allowed and supported tethering, the options would just disappear because the APN settings for the carrier were not present in the phone and couldn't be uploaded on some iOS versions.
I ditched my iPhone when I got tired of my tethering options randomly disappearing/reappearing on minor iOS updates without a chance to override that. Even though my carrier allowed and supported tethering, the options would just disappear because the APN settings for the carrier were not present in the phone and couldn't be uploaded on some iOS versions.
Somehow Android "just worked". Figure that.