The death of the narrative
Initially, the wins came hard and fast. Rudd started by pretty much immediately setting the ball rolling to end the Pacific Solution, ratifying the Kyoto Protocol as his first official act as PM and formally apologised to the Stolen Generations in his capacity as the first course of order in the opening of Parliament after the election. Work Choices was virtually completely reversed, with some elements retained. A deadline was set for the removal of operational forces within Iraq (and followed).
But it was maybe a case of too hard and too fast. As time went on, it started to seem like Rudd had run the horse upside down. We got giddy on change.
And the easy change was all upfront, the hard wins were still to come.
The carbon-emissions trading scheme was already promised, and the Garnaut Report (a bed he'd made, or commissioned at least, before even becoming PM) fell in line with it, suggesting targets that would be achievable, but not without some stress.
Rudd had made the mistake of saying that climate change was "the greatest moral, economic and social challenge of our time" while in opposition. In some respects, unless you don't believe in it (in which case feel free to put your hands back over your ears and scream "not listening") he is right, but in hindsight it was a foolish thing to say. How many times have these words been parroted by the opposition to tar and feather Rudd?
The ETS/CPRS became an essential part of the Rudd narrative. It didn't get through parliament.
The Henry Tax Review fell out of the well-meaning but mostly useless 2020 summit. It was necessary, but it set another issue in the Rudd narrative. The Rudd government sat on the delivered report for almost 6 months before addressing essentially none of the items and delivering the RSPT. I should note, I don't disagree with the RSPT, but for a government that came into power telling a story, they couldn't sell this one to a nation that the polls suggested already agreed with it. It didn't get through parliament.
This was the problem with the mid-term big tickets for Rudd - they needed to get through parliament. When they didn't get through, they needed compromise. The problem with compromise in terms of something like the CPRS, is that if you compromise on the policy, you... well... compromise it. The CPRS was about as paper thin as it could possibly be to start with - it was hardly stringent, and if anything it read like a token gesture, at best a step (baby step) in the right direction (or this was how the pragmatists in the Labor party tried to sell it). To compromise further, unlike with a lot of policies, opened the door to criticism of its token nature.
The Liberal leadership spill happened. Support for the CPRS from Turnbull's Liberals dissolved into pig-headed "it's either too expensive to tackle or it doesn't exist at all so let's call the whole thing off" arguments from Abbott's Liberals.
The stimulus package was almost universally declared by economists as the reason Australia staved off a recession during the GFC. But Rudd was unable to sell the benefits of the short-term debt because the Australian public are averse to debt; for many it reconfirmed their concept of the Coalition saving money and the ALP spending it - and the opposition cynically pursued this angle for the politics, rather than taking a bipartisan approach when the economics stood up.
The Rudd narrative died a slow, prolonged death. The polls turned, dramatically in the context of a narrative where we had the longest honeymoon period for a PM ever, scoring into the 70s in approval records, but not so dramatically if we compared it to more realistic numbers experienced by governments in, say, any period of modern politics. Ever.
We can talk about what happened on the night of June 23rd, and the reasons for the spill, etc etc. But the thing that killed Rudd, in the end, was the fact that a narrative had been built that couldn't ever be followed to its happy conclusion in a parliamentary democracy, or, realistically, had no planned end. The tide was always going to turn; it was only a matter of when.