There may be some Ponzi aspects to US Federal budget, but that isn't it.
How is transferring money from workers to non-workers is reminiscent of a Ponzi sceme in any way? There's no imaginary wealth being created, it's just a transfer of wealth from younger to older generation. I wouldn't bet that future young will be as silent about it as we are, but I wouldn't completely discard it as a "Ponzi scheme" either.