The night the accessory patch went live, I saw iron lockboxes going on auction for around 30,000 crowns. But the price has dropped steadily since then, and there's now an entire page of iron lockboxes on the auction house with a buy price of 3,050 crowns or less. And it was more like 4,000 last night, so the price is still falling. I saw one with a "buy now" price of only 1500.
The lowest buy price for a silver key on the auction house is 53,999. Which is idiotic, because crystal energy is selling for less than 60 crowns each, so you could buy your own silver key from Boost for 45,000 crowns, but that's still fifteen times the cost of a lockbox.
The point being, there are clearly more lockboxes being found than being opened. Thus, supply keeps going up, the price keeps going down, and we can reasonably expect it to stabilize at something very close to zero. The value of the lockbox itself is quickly becoming negligible; only the keys matter.
Perhaps this is intentional. Maybe the goal is really to sell as many accessories as players could possibly want for approximately the cost of silver keys, so they expect that everyone will have one or more lockboxes basically all the time, and the sole and entire purpose of the boxes is a psychological trick to make players feel invested so that they'll buy more keys. I think that's kind of tacky, but I would understand it.
However, if that is NOT the intention, then EITHER lockboxes are too common OR silver keys are too expensive.
This isn't some whiny sense of entitlement saying that I should be allowed to purchase accessories more cheaply than that--I honestly don't care about accessories, I wouldn't buy silver keys for 50 energy, and I am fully in favor of sucking as much cash as you can out of the players with too much money to spend so you can fund further game development and deter them from bidding up the price of other goods.
Rather, this is an objective conclusion based on empirical data and basic economic theory. The number of people willing to buy random accessories at the current price is simply less than the number of lockboxes being given out. (And I care because I want to profit off of the players who want accessories by selling them lockboxes, I admit it. But that doesn't make this conclusion any less true.)
The devs presumably have access to better data, so they can check for themselves: is the number of unopened lockboxes in circulation stabilizing, or is it still growing? I'll wager it's growing rapidly. There's 27 pages of them on the auction house, that's more than ALL type of accessories COMBINED. It hasn't even been a week and lockboxes already cost less than 10% as much as keys.
If you want players (other than complete newbies) to care about finding lockboxes, I'm pretty sure a change is required.
It'll stabilize based on the relative value of the silver keys and what the accessories themselves sell for in the AH. Essentially, the value of a lockbox is roughly the average value of a known accessory (taking statistical distributions into account) minus the value of a silver key, minus a small margin to cover risk.
So let's say a key is worth roughly 45kcr, and a weighted average price of accessories is 50kcr, then a lockbox will be worth slightly less than 5kcr.