This only talks about rent. And when rent increases, so does the value of the property, because you can get more money as rents are higher.
If you now consider the amount of work you have to invest into owning property and the associated risk of owning a house or flat, in an ideal market its simply not possible.
And while the housing market is imperfect due to the high burden for entrance, I have never seen a proper calculation where mortage, insurance and maintanance comes out lower than renting.
And, as a matter of fact, it doesnt even in your own example Sydney: https://www.smh.com.au/money/saving/as-costs-soar-is-it-cheaper-to-rent-or-buy-20230407-p5cywp.html
The 20 % deposit has to be taken into the calculation as well.
You are completly neglecting insurance.
You are negleticing maintanance.
You are comparing two different properties.