If you like this kind of behind the scenes, i highly recommend Ken Kocienda's book "Creative Selection" about the development of some parts of the first iPhone.
Totally agree; it's really fun to hear how things like autocorrect evolved over the development of the iPhone, and really how the designers and engineers thought about their work at the time. It's also nuts to think that so much of the iPhone software and experience was done inside of 18 months.
Thanks for reminding me, this is the perfect time to finally read that book.