A scheme where previous owners sell an asset to later owners is not a Ponzie scheme. It's simply capitalism.

You can tell the difference between a Ponzi scheme and capitalism with the following test: what happens when the money stops coming in? In a Ponzi scheme the system collapses. No one has any asset of any value at all. In capitalism the asset just costs less.

An example is bitcoin. When people flee bitcoin after an exchange goes down or China passes an unfavorable law, bitcoin still has value. In all cases bitcoin holders have been able to go to an exchange and trade bitcoin for some other asset.

In a Ponzi scheme this can't be done--the asset is literally worthless.

I hope that helps.