You don't need to cut gold in half if you make sure there's something to spend it on in the campaign.
This. I just finished the mega-dungeon I was playing in today, and we have something like 30k in gold laying around at level 9. Everyone wants to head to a major city to spend our gold, and I'm thinking "100 healing potions, 10 more healer's kits, 5000 gp in diamond dust...what are we going to do with the other 20k?".
And sure, you can make magic items available (and I know our DM will, when we get back to that campaign), but there's really only so many you'd want to have, and there's some you probably don't want players to have (we found a Cube of Force and a Horn of Blasting in the BBEG's lair and I'm scared...).
For my campaign, I'm going to need ways to make money investments that do things the players will care about. Every game I'm in, we go out of our way to make a base of operations, but then we basically never go back to it (in a Fantasy Craft campaign, I received the deed to an Inn as a quest reward and I kept throwing money at it to upgrade it, but we never did go back to that town).
I have some NPC's who can train players in various things with some downtime, so that might burn up a little- in Fighter's Challenge you're meant to return a chunk of treasure to the town, and I certainly made doing just that have benefits (so hopefully the PC's don't take the money and run, lol). There are hirelings available, some good, some...yeah.
But the big wall I keep running into is that I don't want gold to turn into just another kind of xp, where it's just a way to get power in a different way than leveling up- I want it to do more, but the essential D&D game loop is adventure > grow in power > more adventure. Even if you add rules for keeps and followers, it's mostly just busy work if the heroes keep wandering the world unless I want to try and incorporate some kind of mass combat system.
And I don't want to create a money sink either- with that, I could just as easily have them run afoul of taxes or thieves, or not give them treasure at all!