Artificial scarcity serves several purposes:It gets people to pay more attention to the gem shop generally, which generates more sales.It counteracts "familiarity breeds contempt," i.e. people tend to discount the value of things that can be obtained at any time.It adds incentive to "impulse buy," because you can't be sure when the item will return. It also has downsides, including annoying some players enough that they simply don't check at all. However, in the last few hundred years since the practice got under way in an organized fashion, retails have gotten pretty good at it, so for every dollar to a user becoming jaded, they usually get several more dollars from the rest of us who keep a watchful eye. tl;dr Why do they do it? Because it works to make more money than leaving things available 24/7 and 365 days. Thanks for the reply, If only we didn't live off of money and people aren't so greedy, this would've been a reality. :(