I had a look into this a while back, I could only find a single person who became a startup paper billionaire and then lost it (Jay Walker of Priceline.com), I

I had a look into this a while back, I could only find a single person who became a startup paper billionaire and then lost it (Jay Walker of Priceline.com), I suspect that the reason for this might be that while valuations may be off, they're unlikely to be off by an order of magnitude.