Maybe you are right, maybe not.. However Facebook as an example seems entirely irrelevant, though? It was valued 15 P/S ratio at IPO and went down to 10 a year after the IPO. You'd have a point if Facebook IPO at $400 instead of $40. But it took it 10 years to reach that.

SpaceX IPO price already has many years of extremely high growth priced in. Comparing it to Facebook's or Google's IPOs is like apples to oranges.