You are absolutely correct. The biggest contrast between India and Australia is the way youngsters are introduced to the game from early ages. In India, we just start playing cricket, without any coaching, nobody to correct our mistakes, no equipments, no grounds, nothing. By the time they are introduced to big league, they pick up vulnerabilities that are not easy to fix later in the career. In India, a lots of raw talent is wasted because of lack of early coaching. Do we care about fitness until getting the selection to the Indian team? In Australia, kids start off with proper training and equipments. And they constantly revaluate to fix their flaws. Thus they create excellent cricketers out of average talents.
No wonder Australians keep on winning consistently.
