That said there’s any number of debates you could have:
Was FTX a deliberate ponzi?
Was FTX a ponzi but they were too naive to understand that?
Was it a ponzi within a ponzi? (I.e. has all of crypto been a single giant ponzi with nested levels all along?)
Regardless of what anyone thinks, you only get confirmation either way after the fact.
It'll either:
1) Stagnate. You'll need to wait a really long time for answer.
2) Crash or trend to zero. This would mean momentum is exhausted and money is leaving the table - it's always been a Ponzi in this case.
3) Continue until it finds a utility or it genuinely becomes a store of value. I doubt this outcome very much (I actually think it's impossible due to inherent features of bitcoin), but what do I know? I'm just one person on the internet. Not a Ponzi in this case.