FCA Proposes a Merger with Renault

If Australia would have put heavy tariffs on their ute's like the US does with their trucks, then it would force these trucks makers to move their factories to Australia instead of in Thailand

No they never built them in Australia, so 25% on something that does not exist does not make sense. Losing their subsidies made US owners shut down manufacturing not Tariffs. FTA' are recent phenomenen , cheaper Labour and efficiencies due to many manufacturers in the area attracted other manufacturers