Disclaimer: This topic's purpose is not to discuss if anything SHOULD be done about the inflation of the crowns, but rather if the devs were willing to do something, then which would be the most efficient way.
A year ago, crowns used to cost 200 gold each. Now they cost around 1500 gold each, or 7,5 times more. The reason for this is simple: as time passes, more and more gold is generated and stored within the player population. And the more gold they have - the more gold they are willing to spend. Since the biggest gold transactions happen between players, the gold is only being redistributed, instead of being "consumed". There are very few things that you need to buy from NPCs for gold, and they are usually cheap. The expensive things (like houses) are one-time-purchase. So the game is simply lacking a "gold sink", which is the cause of the gold accumulation and the price increases.
On the other hand, we are constantly getting new things to spend crowns on (such as crates), so there is a constant "need" for crowns, and unlike gold - all of them are being disposed of, rather than being redistributed.
When on one side of the scale you put a resource that is constantly accumulating, and on the other side you put a diminishing, scarce resource, then it's normal for you to need more and more gold to purchase the same amount of crowns.
Before I go into "how can we deal with the inflation", I'd just state what would be the pros and cons of this:
Pros: It will be easier for new players to get into the game. The gold generation rate for new players hasn't increased much, unless they actually know what to farm, and sell what they get in the Auction House. But that is not the profile of the average new player (afaik), and therefore the majority of new players is facing bigger obstacles that they need to overcome, than old players had to face in their early days.
Cons: Dealing with the inflation may lead to less crown purchases, depending on the way it has been dealt with. So the management team would have to think if they want to bring more new players into the game, or keep milking the current ones for as long as possible.
And now let's get to the main part of the topic:
1) Introduce a gold sink - bring something to the game, that costs a lot of gold, and is not a one-time-purchase. Like some extremely potent food/drink, that costs 1 mil gold per piece.
Pros: this is the least intrusive way to deal with the inflation. It targets the "accumulative" property of the gold. Would be healthy for the game to have a gold sink, even if its purpose is not specifically to reduce the price of the crowns.
Cons: it may be the least efficient way, if the "gold sink" items are not desirable enough.
2) Make a 1-time gift of 5000 crowns to all players. When the amount of crowns in the game is increased, their value will drop. Players, who needed 3500 crowns for something, and were looking to buy them, will now have 1500 crowns, that they'd want to sell. The market will be saturated quickly, and this will lead to reduced prices.
Pros: It will be highly effective, and it can be presented as "a Christmas gift", for example.
Cons: It's a short-term solution, and would need to be repeated occasionally, if it's to be effective. This solution may lead to losses in revenue, and it doesn't take care of the core of the problem.
3) Gift every player 150-250 crowns every month, even if they don't have ESO+. Similar to solution 2, but in a more balanced manner.
Pros: It will reduce the demand for crowns and thus their price.
Cons: It will not take care of the core of the problem. It will require a few months before the effect of this is felt.
4) Allow players to buy crowns for fixed amount of gold (and vice versa), from designated NPCs. This way the value of crowns will be determined by the game, rather than by the "free market" within the game.
Pros: simple, secure, effective. It works as a gold sink, since players will be disposing their gold, when they are purchasing items for crowns, that they've bought with gold.
Cons: may lead to a loss of revenue, if the price is set too low. Could be counter-productive, if the price is set too high.
Additional thoughts: Introducing new, desirable items for crowns, will be an effective way to control inflation in the future, even after this system has been implemented once. Since this system will be depleting the players' gold, if the demand for crowns is too high, then players will still need to be purchasing crowns the regular way.
In my opinion, solution (4) is the best one. Although, a combination between solutions 1, 2 and 3 could also be effective. Introducing a gold sink, while also starting to give players a sustained amount of crowns every month will keep the crown price in check. While the immediate gift of higher amount of crowns (could be 2000, if done in combination with the rest) will help with bringing down their price more quickly.
I highly doubt that anything will be done in this regard. Especially when we take into consideration how Zeni refuses to even give us a secure way to trade crowns between each other. But sometimes it's nice to speculate, and I kind a wanted to bring their attention to this problem, regardless if they're willing to solve it or not.