The Australian Labor Party was originally established as a workers' party. Trade unions & much more "left" than under Keating, Hawke, etc. It re-defined itself to gain a broader cross-section of voters. The "old" Labor was considered too marginalized & not appealing enough for middle class voters. Not a vote winner. The transformation from "old" to "new" has been so complete that on many issues the Libs & Labor have almost identical policies. And they DID become more successful. <sigh> There you go ....
Other Oz A2Kers may have different interpretations. This is how I see it.
Pssst ... I have a soft spot for Tony Benn.