> All models are a ponzi No, they are not. “A ponzi” is a fraud. Some of the schemes you mention are not sustainable under certain hypotheses, but none of them

> All models are a ponzi No, they are not. “A ponzi” is a fraud. Some of the schemes you mention are not sustainable under certain hypotheses, but none of them have the deceptive and fraudulent aspects of Ponzi schemes, which is important. These are strategies, that might work out or that might not, but in any case they are not tools for personal enrichment through deception.