But its nothing like a ponzi.
Miners mine the bitcoin. Existential arguments aside for now, we assume IT is a thing, it is on the bitcoin ledger and thus now existing. The miner now has a thing, the miner goes to the market and sells it, and then that thing is bought, sold and traded and exists (again putting aside the question exist). A Ponzi is robbing peter to pay paul, where nothing exists i fail to see the similarity.