I'm afraid I largely agree with TPTB_need_war; without a voting history, I find it hard to see how there can be a reliable, unforgeable consensus for 'now'.
That's not correct, the consensus now is all that matters. For instance as humans we don't have a record of all governments and all decisions going back to the beginning of time yet we have a consensus about what we agree to at this moment. A historical record can be interesting but the only thing that matters is consensus at this current point in time, only historians care about anything else and currency isn't about a history lesson.
This is true in the real world because time travel is impossible. Cryptocurrencies must strive to make time travel, voting on past history, or presenting fraudulent histories very hard, or the 'now' won't be reliable or consistent.