Saying that the value is way less than the price, is not the same as something having no value (your first sentence).
Your examples contradict your first point.
Tulips have value today, a lot less than the bubble. Sacramento real estate has lots of value today. Pets.com was worth something even when it went bankrupt, even as little as it might have been.
$4.3 billion isn't a very big bubble besides. Not even a drop in the ocean of global currencies.
