You are right to a point but central banks are likely to be able to keep the charade going for a few more decades at least. You can invest in a ponzi, knowing it's a ponzi as long as you think you are in early enough. I can't say I'm 100% sure it's a ponzi but I'd say I'm 99.99% convinced.
It's no skin off my nose so please feel free to ignore this but if you want a little friendly advice, read the post linked below with an open mind, then get your money out.
https://steemit.com/bitconnect/@crypto-investor/the-bitconnect-whitepaper-maths-of-a-ponzi