Bounty hunters are alwasy blame for selling their tokens so quickly without waiting for the project develpment as outline in the roadmap. I don't think bounty hunters are to blame because a lot of bounty hunters hold their coins for years.
It's important to consider volumes. Many people who bought in at ICO will be looking at the long-term, and not even put their coins on exchanges.
If a coin drops 90% from ICO price, but the only coins being traded are those from bounty hunters, then really it would be impossible to build up much of a dollar profit if there are only a small number of orders to fill. So for low volumes, the 'price' on an exchange isn't representative of the worth of the project.
If there is a total supply of 1 million tokens, and the exchange has only one order of one token priced at $1, this means the marketcap calculation is $1 x 1 million tokens = $1 million. Which is obviously nonsense. If that order gets filled and someone else puts on an order of 1 token priced at $2, it doesn't mean the project has now gained an extra $1 million in cap.