This is actually very interesting. Although i'll be honest I didn't read much of the above posts/I might be deviating.
When we're talking elite level in many sports there are significant influences:
1. Natural genetics (height, stature, athleticism, speed, coordination) - These things can be improved and refined but only to a certain extent, reality is the limitations are largely natural no matter how much and how hard you work.
2. Socio-economics - This goes to the above point about improving and refining, we see particularly in the Olympics the difference between two unbelievable athletes can simply be coaches and technology in getting every last bit perfect. Asian nations tend to be developing nations and don't have the development tools of our AIS or the US or UK. With that being said, we're seeing great improvement in India's athletes and China has been focusing more resources into their talent. Smaller Asian nations don't have the resources quite yet.
3. Geography - Of less importance when it comes to basketball, but in some sports you see serious advantages where those who live up high above sea level in mountain areas tend to do quite well in sports that require endurance (ie Kenya and marathons). From a slightly different aspect of this point, somewhere like China or Japan might struggle to have the space for track & field, or basketball courts or football fields which again deters talent from coming out of these places.
4. Sheer population stat in terms of overall population, figure of population which participates in sports and figure of population which participates in a particular sport. For instance, Australia is unlikely to rival the US or China in sheer number of talented athletes because we've got a population of 23ish million. Further not a great amount historically played basketball at elite levels because of the transfer to AFL which values similar skill sets (although the Americanisation/globalisation of society and the fact it is easier for Australian talent to find college bball spots is starting to increase our NBA/talented basketball numbers instead of going to AFL).
I gather Asians (whether it be Filipino, Chinese, Australian-Asians etc.) are pretty enamoured with basketball which is great, so the question why they aren't really all that successful or prominent in regards to Australian-Asians probably falls under the four points above.
Ironically, the Asian basketballers in the NBA have been very, very tall (hello Yao and Yi). With that said as a natural populous genetically they're traditionally too small for elite (NBA/International) basketball. For lack of African.... or even Caucasian height, there's also a lack of a Caucasian type broad body (probably one aspect as to why Australia is so good at swimming).
They struggle with height factor, physicality and i've noticed this tends to make them very erratic. Watching the Chinese National team is an ode to this, they've never really been a solid clean-skilled and coordinated bunch, they're forced to rely too much on effort. There's every reason for Australian-Asians to have the same problems associated from a genetic aspect.
Given that there is such a large Asian population, they're developing and starting to pump in more resources - and they're very basketball focused, I think statistically we're bound to see an increase in basketballers whether it be from Asian countries or Australian-Asians. This can only be a good thing in terms of talent associated with the sport and the spread of this world game.