It does not matter that the stocks have been replaced it's irrelevant and completely beside the point.
It's an index and anyone can match the index by buying the stocks or investing in a fund that does.
Let's take 1971 since it was your suggestion.
In 1971 gold was $41, now $1280 up 31.2 times.
In 1971 the DJIA averaged about 850. The DJIA has increased at 10.5% annually including dividends reinvested.
A compounded rate of 10.5% since 1971 would make the total return 75,983
75983/850 =89
Since 1971 gold up 31.2 times, DJIA with dividend reinvested up 89 times.
