The difference between a ponzi and real finance is mostly lying.
In a Ponzi you lie about asset growth. In real investments you report real asset growth. If the system fails it won't be because people lied about what their assets were. It might be because they mis-estimated what those assets were worth. But that isn't a Ponzi.
Crucially though, it is actually possible for assets to grow. As long as there is new good business to finance, the whole thing doesn't need to be zero sum. And annoyingly, growing business is so much faster with a conplex financial system, that countries with such financial systems stand no chance. So even if you don't like the risk and excess in a complex financial system, it's really hard to go without.
In a Ponzi you lie about asset growth. In real investments you report real asset growth. If the system fails it won't be because people lied about what their assets were. It might be because they mis-estimated what those assets were worth. But that isn't a Ponzi.
Crucially though, it is actually possible for assets to grow. As long as there is new good business to finance, the whole thing doesn't need to be zero sum. And annoyingly, growing business is so much faster with a conplex financial system, that countries with such financial systems stand no chance. So even if you don't like the risk and excess in a complex financial system, it's really hard to go without.