Odd hill to die on, but if you wish to argue that Iowa City is a serious transit city, but Brisbane and Lanzhou are not, feel free to state your definition of serious transit city. These cities are bigger than Iowa City and their public transport share of journeys to work is higher than any similarly-sized U.S. metro area.
Beware: if there are no true Scotsmen left, and your definition of serious transit city excludes everything apart from ~10 European cities, the conclusions that one can draw from the policies of serious transit cities will be so limited that they will in fact be useless.
That doesn't make it a serious transit city