Complex sentence: It was anticipated that Australia, along with many other Western nations, would experience a major demographic shift in the coming decades, resulting in the anticipated increase in age pension payments placing an unaffordable strain on the Australian economy.
Split into simpler sentences: It was anticipated that Australia, along with many other Western nations would experience a major demographic shift in the coming decades. Hence the foreseeable increase in age pension payments would have placed an unaffordable strain on the Australian economy.