IMO this should be called a pyramid scheme.
In both ponzi and pyramid schemes all profit from users come from other users investments.
The difference is that in ponzi you don't know it comes from other users, in pyramid scheme you do know.
Since it is no secret that your profit comes from other users investments, this is a pyramid.
You're right!
We're paying each other and little fee to admin.
This scheme is working while it has active users and new coming ones.
I'm in this game and watching my bets.
Losers are only inactive gamers.