Given that Australia follows the Westminster system, and our government is a representative one (i.e. we all vote to choose our own electorate's representatives), then no Prime Minister is 'voted in' directly by us (well, unless you live in his electorate). The party with superior numbers in the Legislative Assembly has a leader it elects, and that party is invited by the Governor-General to form government. If the party elects a new leader, then they by definition are the elected Prime Minister.
And if you're suggesting that K. Rudd was any less beholden to the 'big, bad Unions' than J.Gillard, and secured his leadership solely with the aid of non-union aligned factions and a bit of magic pixie dust...
It's like complaining a vote for Liberal is a really vote for Corporate Swill-meisters: the power bases of the major political parties have been pretty much as is for all eternity.
I didn't vote for K. Rudd either, but all the best to Ms Gillard. Just please Julia, dump that dead arse Conroy and whatever wheelbarrow he pushes, tell Fielding to stick his poison apple support, and get on with the job.