> The whole point of original rule was to have market discover price over time before adding a company.

IPOs and indexes were not really built to handle companies that stay private as long as we are now seeing. SpaceX is trading at crazy levels in the private market right now. Even if it prices down to something ~1T, it would be silly for an index that is a total market or the biggest 500 companies to ignore it. With that said, it'll be float weighted and have about as much impact on the s&p 500 as something like DoorDash.