IMPUTATION! DIVIDENDS! FRANKING CREDITS!
Because of imputation australian listed companies distribute capital via dividends. (most of the time) they dont hoard capital chasing cap gains for stockholders. The reverse happens in the usofa. You may have noticed a lot of companies in the usofa either dont pay divs at all or small ones at best. Its not as tax effective over there as is here. Its truly amazing when you think about the effect of distribution and allocation of capital that occurs because of imputation.
Absolutely useless comparing two market cap indexes against each other. Try comparing the accumulation indexes over the same timeframe which will give a better indication of the true performance received from holding either.