Without the current design, you cannot have a zero trust system.
Most efficient designs are of course possible, but decrease trust. SPV is an example.
Wow, it's really powerful statement and really questionable. I hope it comes with formal proof Most efficient designs are of course possible, but decrease trust. SPV is an example.
Blockchain system can secure almost any underlying data structure (think of namecoin) and I don't see why it cannot be account ledger.