Noone is a bad generalisation here. There are designers and builders who do know and do care - you just pay extra for the design and extra for materials. If you get a project house on a new estate (like lots of people do)... you're basically getting cheap and simple result that's cheap and simple.
Source: talking to a designer about just that.
Most investment properties are done on the cheap, shifting the cost asymmetrically to the renters - cross ref the whole negative gearing debate and all.
Minimum standards need to be increased dramatically, yet very little is happening. When some of the earlier Energy Star "standards" were released a few years back, they were just a bad joke - eg door gaps still came part and parcel, however you'd get like a "solar water heating" checkbox.
It will probably feel useless because it won't make a difference right away, but it's got a better chance of a good outcome eventually than a rant on HN.
I know I froze to death one year in a very cold flat which I couldn't heat with a 1 or 2 cm gap under the doors. Every time I'd cook I'd cut myself because my hands were too numb to control the knife. (The rest of the time it was okay because I'd just wrap up under my doona on the couch or wherever.) Now I live over a bakery in an old building so there's lots of old heat and heavier construction keeping it tolerably warm.