I can partly see the rationale - existing stockholders will want to ditch their stock ASAP to cash in on the artificially elevated prices, and so there's a good chance the free float will increase quicker than the index can capture it, but this rule change will be driving those sales. It's all a scam.
I'm glad a good chunk of my US holdings are in S&P tracked ETFs because they won't include SpaceX until it's ready, but another 25% of my funds are in funds tracking FTSE global indices (so equivalent to about another 15% in US), and I haven't yet found a good alternative to those. I might end up having to switch to separate UK, S&P 500 and global ex-US, but making that switch would probably cost me as much as just sucking it up and being forced to buy SpaceX.
Even with linear scaling, being one third of the way between two numbers is not what I would call underlined-much closer. But zero punches above its weight here. Those extra orders of magnitude should make some impact on the scale.