So, I suppose the first issue here is, what do you consider the "Economy" in this game.
Plat is presented as a precious metal currency but is in fact is closer to a fiat currency that is infinitely generated through little to no effort. To further confound any idea of Economy is the fact your Plat cannot buy everything or depending on the server you play on much of anything.
So is it even fair to consider "Plat" EQ's currency? As far as I'm concerned the answer is NO.
The closest thing to an actual currency would be the Krono. Not only can it be traded for any goods or services (TOS complainant or otherwise) But it can also be consumed for extra game time. Furthermore unlike Plat it's supply is limited and it's generation is confined to those who dump money into DPG's Coffers.
But, that still begs the question... What is an Economy in a game like EQ? Everything on the supply side (except for Krono) is virtually unlimited. TS Mats, Raid Gear, Group Gear, Spells etc etc. Make spells a Billion per copy, Make it a million a day to Rent the effects. Doesn't matter when your Money is fake and it's generation is unlimited.
A better gauge of a servers Economy IMO is how much Krono is changing hands.
Are prices moving up and down. Can you get an order filled in good time. The lower the price and the longer it takes to buy one is suggestive of a dead server.
Wanna see a real horror show for Game Eco... peep out the nonsense over at EvE Online. They post Graphs every month so you can know how many pixel things your pixel bucks can buy.
KR is a fiat/fake currency also. DBG's could go right this second, make 1 million KR, and sell them for 1c each, then all the KR people chase are now effectively worthless. Your last 9 words are the only thing that matters (and goes to show, no game Economy, its generated pixels).
Put it this way:
I work, to make money to play EQ (and food and beer and blah blah blah). I can go buy me a beer, if its the last one, then that beer will go for what people will (plat-flation, KR real life, secondary and in game cost) pay. Until somebody makes more beer (if possible) things are "traded" to have that last beer.
EQ "Economy" last beer? *name your dev* everytime you open a door in the new xpac, you get a beer.. all this can be done with plat, KR, xp.. up or down... and makes for a false/manufactured/fiat "Economy" .