Land-based wealth outlasts money-based windfall wealth
Wealth that comes from working a specific piece of land compounds slowly but durably, because every improvement stays in place as a new field, a new building or more livestock. Money that comes from speculation, like Geissler selling the copper-mining rights or the mining boom that briefly enriches the district, arrives suddenly and drains away just as fast. When the mines close, the people who left their land to chase wages are left with nothing, while Isak's holding is still standing.