Well there's no arguing with that, given that "in its current state" includes what's here. But sports alone did not create downtown Indianapolis. It was a very complete plan. Consider one sentence again from the Wikipedia entry on Hudnut:
Five or so of those were sports-related. Hoosier Dome, Market Square Arena, natatorium, IUPUI track stadium and the ice rink at Pan Am plaza.Over the sixteen years of his term, more than 30 major building projects took place downtown.
The rest (the great majority) were offices, apartment rehabs, medical facilities and other non-sports resources.
No industry benefitted from sports downtown as much as the restaurants, but ask 50 downtown restaurants what they'd do if they had to choose between the "after the game" crowd and the ordinary lunch crowd of office workers. Most would pick the lunch crowd, which is made of insurance clerks, state bureaucrats, cops and lawyers, corporate realtors, etc.