Why on Earth anyone invests in the Australian Shares? (SPX)

The last 16 years. The US S&P 500 index (in red) Vs the Australian All Ordinaries index. The US broad market index up by 607%, the Australian index up by 58%. The US S&P 500 index is a broad measure of the top 500 companies in the US, and the All Ordinaries likewise from the largest 500 companies listed in Australia. The US represents about 25% of Global GDP Vs Australia at 1.6%. The US S&P500 index companies also earn about 40% of their earnings from outside America (due to their Global reach). Their companies also lead in tech, banking, defense etc. Why does anyone invest solely in the Australian share markets? The Australian index is very narrowly weighted to the big 4 banks (mostly leveraged on Australian residential real estate), and the large miners (leveraged on the commodity cycle). Both very narrow, non-diversified risky strategies, and clearly over the long term a crap investment compared to the breath of risk and performance outcomes of the US multinational giants of expansion and leading edge innovation.