On my iPhone, in order to type "I'm," I hit the shift button, then "I" then the 123 button, and the apostrophe, then it switches automatically back to letters, and I find my right thumb is already hovering over the "m."
Easy peasy lemon squeezy.
The developers decided to make the apostrophe most proximate to the M. They calculated, based I'm sure on all of the terrifying data they gather—data that has long since become predictive, so that you think of an old friend and are immediately shown pictures from their feed... or you wonder if you'd ever enjoy hangliding and there are the ads—that iPhone users would most often want to say "I'm."
Not near the D for "I'd" which would lean toward a user's preference. Not near the L for "I"ll" which would lean toward a user's intention. Not near the T for "can't" or "couldn't" —and one can easily imagine the self-congratulating EVP pontificating in a meeting that putting the apostrophe near the T would be to cynical and pessimistic, and the meeting concluding in a reverie of Silicon Valley faux-religious rhapsody. Vibram soles for everyone.
I'm. Identity. I am. The contraption in the user's hand becomes a medium to declare who they are. The contraption becomes a part of who they are, seamlessly and without the friction of having to find the apostrophe and expend any extra thumb energy pressing it.
These corporations pay big salaries to figure out how to slide into the DMs of our very consciousnesses.
And it's working. It IS working.