Because the only reason they bought the bitcoins was to invest for the interest rates? (I'm not saying all pirate investors were like this, but some must have been.)
Why would anyone think it was the majority. You're not invested in Bitcoin but you decided to take the leap because of an extremely risky HYIP opportunity? I would think that's almost no one.
Loss of confidence, hampering the bubble we had.
I think the value without megabulls is below $10.
Obviously if you remove a big chunk of the the population that values Bitcoin, the market price drops. But you can't. So the only value that matters is the one that reflects the behavior of the entire population.