The US has four states with population comparable to Australia.
It would be perfectly centrist for a couple states to enact the policies you mention, assuming they can work out the details and balance the books. When these policies turn into wild success stories, other states might follow.
It probably makes sense to start with some small-medium sized, well-governed blue states first, like when MA implemented Romneycare.
But the left position is to enact these polcies nationally across the US, which has >10x the number of people in your country. And there are a ton of details that nobody really even wants to talk about, and no plan to adapt when things don't work out. So, we are just supposed to trust Congress with a huge amount of extra money and a lot more power because the title of the bill sounds nice?
There are also a lot of policies that seem uniquely designed to punish the "right". I am pro-choice, but I recognize that a lot of people in the US are really, really not. But a lot of people on the left don't just want it legal, they want to use taxpayer money to pay for it. Think about how that makes tens of millions of evangelical Christians feel? There are enough pro-choice organziations that they can pool money from pro-choice people to subsidize abortions. The taxpayer money isn't needed. Why force it?