Because he's such a good boy!
Ask An Australian
I watched some YouTube video suggesting Australians have the biggest houses in the world, could have something to do with that?
It is interesting because cats (a common pet) are a huge problem for native wildlife. But I don't know why, beyond it being normal and people often having the means to provide for a pet.
Recently I've seen lots of people adopting former racing dogs after a lot of news came out about ethical concerns in the greyhound racing industry.
Because dogs are rad
Because we love animals and nature and have the space.
We have very high per capita income and GDP, as well as a lot of land. Until "recently" you could expect to buy a house with a backyard on a median income. This probably has contributed to it, but I couldn't tell you why we would beat the US.