As bad_advice said about living in a country where it's illegal NOT to vote
my view is there are 3 main processes at work here.
1 - Political parties platforms cater to the LCD (Lowest Common Denominator to you LCD's). Whether it's the bogans/chavs/rednecks pissed off 'cause they have to do something other than get pissed on a Saturday or the mortgage belt 'wearers' shitscared of a government that's going to raise taxes or allow home loan interest rates to rise or the OAP's worried about their investments and self-funded retirements (let alone the joke called a pension).
They're all going to vote "middle of the road". Not conservative and not socialist. The white dashes in the centre of the tarmac.

2 - This demographic is what the parties aim for. Thus "The Left" swings in and so does The Right until you have 2 parties that basically end up squabbling over what "middle ground/don't rock the boat" policies they can come up with. Unless they can find a scapegoat like say... immigrintz!
This is where the real mud-slinging and personality politics comes in. As we saw over here recently. There aren't I think many people who genuinely think Tony Abbott has a towering intellect - his "Prince Phillip-o-metre" goes to 11. But compared to the "fair shake of the sauce bottle" who gave his leadership and our prime-ministership to the Scarlett Harridan - Tone the Boner looked fucking great.

3 - Finally.
The fringe-dweller, hangers-on, nutjobs and (sadly, frequently) powerbrokers.
As we are under the Westminster parliamentary system under a 2 party-preferred setup basically any weirdo fucking nutter can start a political party or run as an independent and use any votes they garner as coin to leverage the two major parties into doing what ever the fuck they want them to.
Some people see this as "checks and balances" against the major parties having a balance of power.
Yes that is a bad thing but the senate is always a good stopgap against the lower house. Letting the "independents" have the balance of power is letting the inmates run the asylum. Think I'm wrong? 2 words - Clive Palmer.

Thanks to the rest of you for listening. To the poms you may not agree (or even understand) but then from what I know you have an OAP who let Rolf Harris paint her pic, who gets to "give" titles to people who aren't elected but still get to run the country.
(s0ckpuppet logging out to reply to you if you're not careful, Thu 17 Oct 2013, 6:38, Reply)