The financial incentive to run a minority client.

So I sent a tweet and it got a nice conversation going in the replies.

I will summarize here though.

So we have been banging on about how client diversity is important for the beacon chain and have been encouraging everyone to run a minority client to improve the stability and resiliency of the beacon chain. This should be a good enough reason for anyone to switch, but I get it, once people get a node and validator going they don't want to mess with it.

What I think we haven't focused on enough is the financial incentives to run a minority client. Right now Prysm is approximately 65% of all validators. This means that if there is a bug in Prysm, and it forks off to its own chain, 65% of the beacon will be down. Right now having some down time is no big deal because the network is 99% live and the penalties are small. As more and more of the network goes down, the penalties increase for everyone exponentially. At only 35% participation the penalties for down time will be significant.

But that's not all. It gets worse. Because Prysm is so close to the 66% required for finalization, there is a chance you attest/propose a block on the forked chain. If that chain manages to finalize there is no way for that 65% of the network to rejoin the original chain without being slashed. If 65% of the network gets slashed simultanesously, you will lose approximately 75% of the balance of your validator, so 24 ETH.

If you are running a minority client and the same thing happens, you get a much smaller penalty for having been offline as less of the network is down, and there is nearly 0 chance that the forked chain finalizes meaning you will not get slashed when rejoining.