I spent 20 million in 2 days (mostly on sealants). I make my own gil. It's not impossible with high level crafting. That person most likely crafted 3 and 4 star furniture. Sealants are easy money even for low level crafters. There ought to be a lot of money swishing around. And lots of people, like myself, came into 2.4 with a good amount of gil on hand for the inevitable outlays.