Apple should do a lot of things but they are only going to do what makes them the most money or saves them the most costs: As longs as there's no clear indication that Apple is losing market shares because of it's refusal to go USB-C for iPhones then there's no reason for them to change anything and waste money on R&D.
Giving iPhones USB-C renders a ton of proprietary, made by Apple-accessories obsolete and opens up the market for consumers to get cables and chargers that are neither made by nor mfi certified by Apple.
Judging by what Apple is doing with MagSafe, I feel its much more likely they'll rely on some iteration of that or come up with yet another new proprietary solution. Equally likely is a portless iPhone with upgraded wireless charging speeds, "MagSafe 2nd Gen" or something similar.
Businesses only care to impress as long as it means increased profits. If consumers buy the product even when parts of it are disappointing then there's no reason for the business to change the product.
I'm also sure that there are just as many Apple users on the other side of the fence who have invested hundred of dollars on Lightning accessories and would hate to see the port go.
The win that many are painting a switch to USB-C to be for Apple isn't as obvious as it's often made out to be.