It starts in 1989 with Exxon, IBM, GE, Bristol-Myers-Squibb, and Merck in the top 5 spots. Honourable mention to Verizon, AT&T, 3M, AIG, Boeing and Pfizer, who were in the top 20. With the exception of AIG, none of them are bankrupt, but they have not provided good returns, and with the exception of Walmart, not a single top-10 company is still in the top 10, 35 years later.

But isn't this a factor IN FAVOR of cap weighting as opposed to equal weighting? If you cap weight, as the companies go out of favor, and as their market cap drops, the percentage they comprise of the index also drops. Meanwhile, when they are equal weight, the percentage they comprise in the index remains the same until the bitter end (when they fade to nothingness). Let's say a company is worth $5T and is 7.12% of the S&P500 index. And let's say that company has issues and next year is only $3.5T, then it'll go down to about 3% of the index. And let's say the company continues to have problems and drops in value to $1T? Then it'll drop to only 1.5% of the index. Meanwhile if it were equal weight, it would be 0.2% of the index at $5T, and 0.2% of the index at $3.5T, and 0.2% of the index at $1T. And if it heads to failure and nears the zero value, it'll still be 0.2% of the equal weight index as it becomes a zero (or gets removed from the index altogether).