What if the role of David Helfgott had been open 10 years earlier? Mr Rush would likely have wanted to go up for the audition. But, he wouldn't have been the right age to play him; he might not have had enough lived experience, have worked with the right acting coach, had the agent who could get him in the room or fill in any number of blanks to play that role. And had he not been cast in Shine, it's entirely likely he might not also have been cast in the Pirates of the Caribbean franchise, Shakespeare in Love, The King's Speech and so many other memorable films with…