"I suggest our democracy is best served by having different policy offerings, a battle of ideas, vigorous (polite) intellectual tussle and competition."
That's exactly what those who would never vote Lib/Nat don't want. Labor vs Labor-lite is win/win for them.
Trumpy /Brexit/The Voice show that given a genuine choice the people are happy to go against the massive media spin and stand up to be counted.
That choice is what those currently in power seek to deny them.