In order to determine which blockchain is the correct blockchain, Proof of Stake blockchain users need to trust that they have been told the correct account balances.
And along the same lines, seems to me like POW-POS hybrids are only as strong/decentralized as their Proof of Work component.
Do you agree?
Hybrids do not combine the strengths of the algorithms, they combine the weakness.
Most hybrid coins eventually drop the wasteful PoW as it only leaves a 51% attack vector.
PoW is a dead end due to their ever increasing input costs.
PoS is the Future for any coins wanting to survive.
FYI:
Vitalik would not know a True Proof of Stake Design even if it bit him on the ass.