As was shown in Bitshares, which relied on holders of BTS to vote on "good" block producers, users can not be relied upon to make these judgements. They will either vote at random, or vote based on trivial stats like uptime. The holders of BTS ultimately paid the price when the creators of the coin forced through a proposal to increase the supply cap and the price collapsed as a result, but the creators have since moved on to other coins.

It seems to me that proof of work works, and proof of stake (as implemented in Tezos) may work, although it's not been running successfully for very long. I'm very suspicious of other consensus algorithms protecting billions of $s worth of assets.

The crypto space has an near-infinite supply of new coins and new whitepapers to trap the naturally curious into a hopeless cycle.

What if for example with SCP quorum slices form only between nodes of agreeable reputation where reputation could either be transaction confirmation history or transaction participation history or some combination of both.

I would argue,if some form f reputation metric was in play,a simple 51% majority (for unfederated) would not mean much,especially if each node gets to unilaterally decide reputation metrics it finds agreeable which will make it hard for a sybil attacker to know how many nodes of what reputation it needa to control to succeed.where a failed sybil attack could reduce or eliminate reputation of the nodes it used.

The whole idea is so simple I feel a bit cluelees even asking about it,but does anyone know if similar consensus systems have been explored?