Basically, the price goes up quickly when new people are attracted to bitcoin and rush to buy. When the price dips however, because so much is bought for long term speculation, the price doesn't really dip much, as no one is incentivised to sell and hold out for when it gets better.

At some point the nerve of those holding out may crack, but if you read silly saurus2's post, its quite clear that many will hold out indefinitely on the belief or hope it will one day recover. So in this manner the bubble can deflate slowly. (If you call 10% in a day slow).

There are no settlement dates or ways to easily move money out (especially now) so a crash is prevented.

If a crash happens it'll probably happen before people realise it, but suddenly there just won't be anyone wanting to buy coins anymore.

But even that might not happen as people already invested into bitcoin use how wealthy they feel to buy bitcoins from each other. That can cycle for a long time before people realise there isn't new money in bitcoin.

If you had bought coins at 800-1000, why would you sell now? No one likes to cement a loss.

Those with the most reason to sell right now are the early adopters, but it's not actually clear how many of those coins are actually reachable.