how is this possible?

[Fornix]

thats a thing which i dont get aswell:



always the same handful of players buying all pets and expensive crafting ingredients day for day rediculous overpriced
mog whisker sells for 5-10 mio, opo opo 5 mio, tIV gatherer materia for up to 1 mio ea and the list has no end

That is investment most likely. They may sell for what can be considered a lot right now. But by next year, they'll be selling for e.g. 20 million a piece. Two years from now, e.g. 50 million. Three years from now, e.g. 150 million. Etcetera. Inflation in MMO's is insane. And vanity items, especially hard to obtain ones (which get even more rare to obtain in the future, as the low drop chance combined with the content being run less frequently don't increase supply) will always keep having a market.

So if you have the gil right now, it's a worthy investment to buy up such items and see the future profit as a high interest rate. Rather than simply stocking up gil. After all, 3 years down the road 6 million gil is still going to be 6 million gil.