I am planning to use this TV with Chromecast Google TV. All the TVs which I could find in the market are either Smart or Android. But most budget smart TVs have weak processor and buggy interfaces.
In the US, there are products like Sceptre UTV 50" Class 4K LED TV that fits the bill. What's the Oz alternative?
I don't think there's really a market for dumb TV's anymore, they all have 'smart' features as it's a selling point. Even if it's incredibly slow, the majority of buyers won't even know there are fast and slow systems. They'll just be stoked they have a Netflix button. So I'd say you'll have to buy a smart / android TV, just don't use the inbuilt interface and use the Chromecast instead (though start-up times can get annoying with some of them).