Rachio 3 and Australia - illegal!

That can literally be said for just about anything you buy. Irrigation controllers, home automation devices, phones, cars, electronics. You name it. Everything will be obsolete within a few years with a newer better option to replace it. I think coming into their community with a confrontational attitude trying bad mouth their product is pretty crappy.
Most companies develop for their target market, and offer different devices with different features for other markets based on local regulations. This is how companies have to compete in the global market place. Who knows, maybe someday they will offer an option that is geared toward Australia. I suspect the choice not to offer an Australian variant of the Gen3 likely means to do so was cost-prohibitive given the size of the market. It’s not their fault that the market won’t support the cost to bring the product to it.