Well for one, the price is down by 10% from last week. Whatever was priced in from those 'in the know' a week ago wasn't that big of a deal.

Secondly, the theoretical expectation was always that the value should go to 0. i.e., if parties can steal money whenever they want then the system is worthless.

Obviously there are parties who together form 100% of the mining power, same with 51% of the mining power. They need only come together and decide in order to steal. The only thing preventing this was a bit of game theory about how their coins and mining equipment would become worthless the moment they do this.

The fact that hasn't at all happened means they profited hard. And it means virtually any coin that has a set of investors with similar levels of disinterest is susceptible to these attacks.

My prediction is this: the first attack has little influence, even on bitcoin. It'll be cast aside as some mysterious accident, the theft won't be large and it'll be seen as insignificant, people will remain hopeful. When these attacks happen with some frequency, like once a month and at a large scale, then we'll see trust completely plummet and prices with it.