It's not (all) the mining companies/mining unions' fault, and it's not true that the mining tax is that onerous for the mining companies – but Labor failed to achieve consensus within the party and failed to push a consistent line to the electorate e.g. that by taxing profit instead of production, it actually lowers the risk of new investment. It was a rare case of an unpopular populist policy that burned through a lot of political capital.
(And by the way if you want to talk about things that discourage investment in mining, you only have to look at the insane knee-jerk xenophobia that pops up whenever a foreign mining company that isn't owned by white people wants to invest in Australian mineral resources).
The failure to pass the Emissions Trading Scheme was also a disaster that burned through a lot of political capital. Not only did Labor fail to get the scheme through, they also failed to rip apart and destroy the Liberal party who were completely divided over the scheme and lost their leader over it. It should have been a political bloodbath.
And then they have failed to rip apart the opposition during the subsequent leadership contest, and then take Tony Abbott to pieces 'cos he's none too bright.
The pink batts/dodgy insulation programme was a terrible idea that was done too quickly and was ripped off left, right and centre by chancers. The stupid Christmas Island immigration processing scheme is still in place, despite it costing 3 times more than onshore processing and achieving nothing extra.
And not that the electorate cares but there has been zero progress in "closing the gap" between Aboriginal/Torres Strait Islanders and everyone else. There is a ton of money for ATSI housing that has been unspent while the living conditions of some villages are like shanty towns. The NT intervention has failed and nothing consistent has replaced it. Police and ATSIs are essentially warring parties in some towns. Plenty of towns are utterly segregated. ATSIs constitute a massively disproportionate number of people in prison, in care, falling out of education – all the usual indicators of something going terribly wrong.
Meanwhile, Labor's performance in the States has been abysmal too: the utterly corrupt NSW government has been busy shooting itself in both feet simultaneously over and over again (e.g. Sydney metro – plans basically drawn up in the back of the cab on the way to the Treasury, like the Dog ASBO plans in The Thick of It, a ton of money spent on ludicrous prep work then cancelled; schools refurbishment – huge fraud and corruption in construction of portakabins on school grounds – construction = tradie unions = Labor donors; Kenneally saying she has full confidence in outed Police Minister, just after she sacked him).
But for all of that, Rudd's government hasn't been all bad: ffs, the pain around the GFC has been minimal (thanks largely to the Chinese pumping millions of dollars into the economy buying "free stuff" i.e. minerals), there's been a real move away from the knuckle-dragging style of politics (which I think Gillard is very comfortable in), FAHSCIA funding for autistic parents has been a very powerful but undramatic policy that has paid off…