Hoarding of wealth has a deflationary effect on any group's economy. Just as the dwarves after Smaug hoovered up their wealth. The ease of capturing an asset often depends upon its relative value. In fantasy roleplaying games, the amount of money stolen by a bandit gang might be a pittance compared to a warlord's battle chest, which in turn is nothing compared to a dragon's hoard. Each becomes progressively harder to loot for any would be adventurers.
Now, the vitality of an economy is often characterized by the constant flow and transfer of wealth across several strata and several markets. Diversity is a hallmark of a healthy economy, like a healthy ecosystem. How might one get money flowing again when most politicians come directly from the plutocrat clade itself (if not serving it)? Writer Charles Stross has an idea relating to soft paternalism.
For example, ideas could include financing space colonization or fusion commercialization. The problems would be extremely costly, but also offer the greatest investments over the long term.