Sounds like pyramids, but using Ether instead of cash or Bitcoins. You know that people always will lose money on them, right?
Yes, I'm aware of that. However, I've thought that it may work differently as it would be powered by smart contracts, where it is automated and it could perform well if programmed not to leave the owner of the contract with an amount of your Ether for him/herself.
I used to put my Ether on a Doubler Pyramid, and it worked most of the time, but lately it stopped making payouts, because if the lack of other users putting their Ether on it. As a result, the pyramid was out of funds, thus leaving my payout on standby until today. It has been almost a year, and no luck ever since.
However, I believe that this could be improved, as the good thing that a smart contract has is that it removes the middleman. There could exist many possibilities with this, but in the meantime I will just rather mine Ether than using doublers. Just my thoughts.