Although it's tempting to say that it's because people gave up, I think you're right in that it's more a store of wealth, so people don't want to spend it. Especially if people bought at a higher level than where we're at, they're going to need to HODL until they're profitable. At that point, if they're still anticipating it going up further, why would they sell unless they needed to? There are many networks coming out (or are out) that can do transaction faster and cheaper, that it doesn't make as much sense to use Bitcoin unless the person on the other end of the transaction doesn't have access to the alternatives.