Why is Australia so good at sports?

There are a large number of reasons, but the big 3 are :
1. The government (at federal, state and local level) funds sports a LOT.
2. We have a culture of sports participation that crosses cultural divides. Anybody can have a go, and people are encouraged across all walks of life to do so.
3. We love swimming, and most people learn to swim at a very young age. Australia has done very well at the Olympics so far, but it really has dominated in the pool.

The other thing worth mentioning is that 4 sports that Australia is very very good in, and has a large amount of time and money invested into, aren’t in the Olympics at all - namely Australian Rules Football, Rugby League, Cricket and Netball.

The one thing I'd add is that, unlike the US, which either rejected English sports or made up their own versions, Australia took on most English sports. This is significant because many of the Olympic team sports are commonwealth sports.

We then started to embrace US Sports like basketball and, to a lesser extent, baseball in the 20th century.

Part of this is also a lot of people playing two sports, one in summer, one in winter. So people who play cricket in the summer then play field hockey or baseball in the winter. Or they play basketball in summer and AFL in the winter. Then you get to the age to pick a career you take the sport where you can be paid millions a year or get government training and support through the AIS because it's an Olympic sport.

It all comes down to funding. If the government is serious about building a program, they'll allocate the necessary resources and you'll usually see the results on the field.

One of the things I love about the Olympics are the small countries who qualify in maybe two events. China, US, Australia, GB, etc. send entire armies of hundreds of athletes while these nations of limited means send two. I think about how different their Olympic experience must be. You have the front runners expecting to take home multiple medals in some cases; while for these tiny countries, the parade of nations is literally the high point of the games for them. We did it, we're here. Some individual athletes will leave the games with more medals than entire nations have ever won. But for some, the gratification comes in holding the flag high and hearing their nation's named called.

Because they like Larry Crowne.

We also have to run from snakes and dodge drop-bears when walking to school. 

... having said that, they were after all caught criminals so perhaps they weren't actually that fast after all 🤔.

Always do well first week as they are very good in the pool usually and taper off second week.

Westi nailed it. The government puts lots of money into elite sports for coaching, all the way down to local sports for facilities.

Ths funding goes up and down. After the Montreal Olympics where Australia scored no golds, there was much spending, as also in the several years before the Sydney Olympics.

Unlike in the USA, sport doesn't play a big part at university but scholarships are made to several sports institutes where much elite training happens.

If you look at it from that point of view it's countries like New Zealand, Denmark &  Jamaica that are really punching above their weight in recent Olympics.  Medals per capita Australia are still impressive.

Perceived "powerhouses" like USA, China and Russia are way down on the list