no because not every bubble primarily involves companies that make up a large portion of the S&P500

presently the Mag 7 alone make up 33% of the S&P500 total market cap

in 2007, the _entire_ S&P Financials sector (banks, insurers like AIG, brokerages, real estate firms) was only about 22% of the S&P500; the top 10 banks (with Lehman at #10) only made up 9%.

the S&P500 is now a dangerously non-diversified asset but still used by retirement savings inventors as a diversified one