Ian Chappell once told me in 2008 when i had the chance to talk to him, that Australia's years of success had deterred an entire generation of young Australians from taking up the sport. I found it odd then, as logic would suggest success in a sport attracts more youngsters to it.
It probably makes sense now though. Cricket is different to most sports in the sense very few play at the highest level and through that success period a number of cricketers barely got a look in. It must have had some influence on how a young kid would have seen cricket. While representing Australia is a huge honour, it was incredibly tough for a number of good cricketers for a decade. Domestic cricket is hardly aspirational anyways.
Or may be has something to do with the nation and its focus on sport as a whole. They just don't seem to produce as many great sportsmen as they were.