Yes. Plenty is correct. Fidelity let's you buy SpaceX at IPO with only $2K in the bank.

And there are other reasons to be cautious. Many passive funds don't license the SP500 and instead mirror it with their own synthetic index. They are not bound to respect this decision.

I think caution is most warranted, but I also think it's likely that SpaceX will become a real-life Weyland-Yutani Corporation (i.e. "The Company") of Alien and own space. But I'll be long dead before that plays out.