I also agree that you can buy poor quality wine in Australia.
Gossips is just on that border for me, but my wife is quite OK with it.
There is no reason any wine maker should make poor wine in Australia, but some do manage it.
I do know of a wine maker in the Yarra Valley that had a poor yield one year, and had pre-orders to fulfill. So despite not having enough grapes, they still produced the amount of wine required, and no, Jesus did not work for them, as the wine was very sub par.
Sometimes it is the storage of the wine that makes it bad, not the winemaker.
My previous employer used to buy wine in pallet lots to give away at Christmas. When I went to collect my allocation at the warehouse, I saw that the pallets had been stored on the top rack in the warehouse - in December 😬. It would have easily been 35-40degC up there.
The wine fizzed in your mouth when you drank it and was very "rough". None of my customers got wine that year.