Okay so here's what we do.
We add the totally optional option to optionally display your money in the form of a new currency. I'll call it doubloons right now, but in reality it should be called something better. Anyway, a doubloon is worth 1000 gold. So if the "display as doubloons" box is checked or whatever...
100,867,325g
Becomes...
100,867d (325g)
Basically you have 100k and the gold is just pocket change.
"Dude how is this actually helping anything?"
Hold on, hold on, I'm getting there. Okay so we let people get used to this for a while, right? We make it show doubloons by default and just let people opt out. Now here's where it gets crazy. You're gonna want to crap your pants, but stay with me, okay?
All right, so once everyone is used to this, we make monsters drop doubloons instead of gold. If a mongbat used to drop 30 gold, now it drops 30 doubloons. Stuff like that.
"You want to make mongbats drop the equivalent of 30k each? Are you insane? That's like the opposite of helping!"
No but see we also make all the NPC vendors take an equal amount of doubloons instead of gold too. Why? Because look, if you just divided everyone's gold by a factor of 1000 it would accomplish the same thing, but everyone would riot and then quit the game. This is all a psychological ruse. Instead of making everyone's money smaller, we just make everything else bigger. The whole doubloon thing is just an excuse to chop a bunch of pointless zeroes off of all the numbers and keep us all from going overweight the first time we loot anything.
Think about it. Your purchasing power relative to other players hasn't changed. Nothing about the player-to-player economy has actually changed. A rare that used to cost 100m gold now costs 100k doubloons. You can uncheck a box and still see all your gold if you want and you really like superfluous zeroes.
The only real difference is now someone who kills monsters has an actual chance to catch up to the guy who's been sitting on a pile of billions of gold for years. Now "millionaires" are actually rich. And gold sellers? They completely take it in the rump. Their existing currency stocks are worth less than ever compared to monster hunting, and now there are no checks to dupe to build a new stock.
TLDR: Instead of de-bigulating everyone's money, we re-bigulate prices and loot so that the money is smaller in comparison.