Do you have something US-specific to indicate that this would be the case? Neither empirics nor theory support your claim. https://rangevoting.org/TarrIrvSumm.html
This seems like an odd choice, given that Australia currently has five different parties in Parliament, and has in recent history had a third party be the deciding "vote" on who forms government. It seems like an even odder choice for you to reference it as a counterpoint in this specific case given that one of those parties is literally called "the Greens".