Imagine if people wanted to go somewhere aside from Indooroopilly Shoppingtown or anywhere along a trainline.

Imagine if people want to transport items too big to easily carry on a train.

The problem with this line of reasoning is it basically precludes any change in the future. To break away from car dependency, you have to actually break away from car dependency. There are plenty of existing homes all across the city that are suitable if you need to own a car—almost literally every other home in the city. Building newer high density developments to also be car-dependent is just entrenching the problem.

And fwiw, unless you're driving multiple times per week, it's far better financially to rent a car when you need it. Let someone else deal with the depreciation, registration, insurance, and maintenance costs.

If you're literally in walking distance to your nearest major shopping centre, to multiple food options, and to the train station, it's very viable to live car-free, and only going to become more viable over time.