If people are willing to buy these Edo Jins even when they should be in time limited treasures to be placed in (based on China and what Oasis said in the preview page for 5.0), Oasis and any other business will take advantage of it.

If people are tired of being milked then don't be trigger happy with spending as soon as possible once something comes out. If no one buys once something comes out, then Oasis messed up and will try to increase the # of people. If someone does buy, you are telling them that is the market price of it until their data begins to tell them that the # of people buying is falling. It's been pretty obvious this is happening if you look at the prices and see how they fall depending how long the item has been around and how many people have them.

I should be more clearer. The argument only refers to the few times a ninja/clothing appears in events as that when you see the price change. If a little change in price makes an impact, then I'm sure that's what they care about. In your example, let's say no one bought at 30k but at 20k, 10 people decide to. Pretty sure they will continue until they stop at a price they can't lower.

As for shisui, I don't think they will change it's price until they make him more available. With the lack of options to redeem and the number of people that still ask for shisui, I can't see Oasis have any reason to lower it's price since they know people are still going to pay it's price. Let's look at a ninja close to his price which is jonin Minato. There have been times where his price dropped by a bit and that large drop when he was in Sakura's gift and the only difference is how many people have access to Minato as there were several ways to get him for the past 1.5 years, especially in the first 6-7 months.

China doesn't have a permanent treasure yet (or if they ever plan to) so Oasis could release the limited treasures just like they have done so before in the past with a treasure right before the kage treasure which had ninjas like killer bee and kaze gaara.

Oh you were referring that you saw the price fall for shisui and nothing else? Ok now I understand you meant.

Honestly, it varies between ninjas. Example: Hokage minato was about 200+ per frag in treasures of the sages in 1.0/2.0 and his price was reduced when he started to come back in events. The last time Madara five kage was in lucky stars which was 2 weeks ago, his price was lower than the average price and I haven't compared this week yet. If you are looking for drastic price falls, they rarely happen until you see a trend. Small price fall happens more often but that doesn't mean it's permanent - might be based on where they are located in an event.