TBH... The largest factor in creating gil buyers is a lack of consequences.

The buyers generally are the ppl that want all the stuff in the system but do not want to work the system to get it. This goes also into those ppl paying RMT for clears on high end or endgame content as well.

The game economy in FFXIV has a serious inflation issue which is partially caused by RMT but IMO primarily caused by the game's design on it's own over time. Quests and activities will still generate exponentially more gil than the game's gil-sinks can remove in the same amount of time. The marketboard for the most part just moves it around as only the tax amount is actually taken out of circulation. Someone in SE needs to brainstorm ideas of optional side activites or NPC purchase consumables that would entice players into spending gil on them regularly.

However part of me wonders what ppl actually buy gil from RMT for in this game aside from wanting a large or medium housing plot as doing MSQ on a new character will generate enough gil to make a small obtainable unless spent foolishly or buying those golden mounts from NPC vendors. Are ppl actually just dumping it into stuff on the marketboard?