Where are you getting this from? Basically zero pension funds automatically track any single index. (There seems to be a misconception equating pension funds with retirement funds in general. Pension funds are, on the whole, remarkably sophisticated investors. Many pensions funds were private shareholders of these companies already.)
> Russell is the preferred provider - and they will include SpaceX 5 days after the IPO
Russell has loads of indices. Their total market index will quickly incorporate SpaceX. Same with S&P. There are also IPO indices that will incorporate it on day one, because that's what they're designed to represent.
> Where are you getting this from?
At least it seems correct for a subset that may or may not be representative: “This report intends to provide insights into the overall and asset class benchmarks selected by the 50 largest U.S. public defined benefit plans. [.. ] the Russell 3000 index was most frequently cited to measure U.S. equity performance.”
https://www.nasra.org/Files/Topical%20Reports/Investment/P&I...
You don’t need to track index X to be affected by changes in X. You only need to hold something related to X. Almost all pension funds, heck almost every investment account in the world holds something affected by some index.