Hi Umi
Yes you are quite correct but there are at least 2 ways to treat the total returns.
1) All dividends are reinvested into the identical stocks that made the payment, or it could be an index ETF.
2) Dividends might be required for living expenses for many investors so are never re-invested into stocks.
All this is relevant but it still doesn't negate the fact that for growth over the long term, US markets have outpaced Australian by a ratio somewhere around 2 to 1. I believe that their massive representation of technology stocks, is the greatest influence on the discrepancy.