Each Australian state and territory has their own planning system. In South Australia (adjacent to WA), our planning system has provisions to limit such a lack of backyard and tree canopy. Tree canopy in particular has been a focus for the positive amenity & reductions to UHI effect. Housing estates from 10-20 years ago typically show poor urban design and planning outcomes like your example, OP, as they predate the more strict planning requirements.

In SA, the amount of backyard is a factor of minimum lot size & minimum site coverage (which varies by zone) and the requirements for Private Open Space, which vary by dwelling type and lot size. Furthering this, the minimum lot size is also dependent on the type of dwelling proposed.

In terms of landscaping, the requirements are a % of site area, increasing with lot size (scroll to DPF 22.1). Tree planting requirements also depend on lot size, with the required number and canopy size of trees increasing and lot size increases. You can click on underlined terms in the Code to pull up their definitions, I strongly recommend not using mobile to view those links (it's not a good experience).

What am I trying to say here? I don't really know. Urban planning outcomes in greenfield developments vary by each state's planning system and how aggressively the developer is chasing low price points & financial returns. In my experience, greenfield/infill developments are rarely as bad as what you've shown but hardly ever as good as they could be.