SpaceX likewise is also in a somewhat murky financial position, although I suspect they will come out doing great in the future. My limited understanding is they are avoiding an IPO because their financials are not up to snuff.
AirBnB was heavily derisked before serious investors took notice - YC loves talking about them as an example because they had so much trouble raising a seed round before they skyrocketed into their A round shortly thereafter. Also I suspect AirBnB is actually going to IPO at a lower valuation than their last round, but I realize I am very much an outlier with that assessment.
I understand high risk high reward, but sometimes investors are just being dumb. I feel like you chose terrible examples to make your point. And since all of your examples are private companies it is impossible for us to analyze their finances.
