I speculate it won't stop until everyone has sold their ETH for ETC. This will accelerate as more and more idiots realize that if they don't sell ETH, they will lose all.
Fools are slow to act until they panic at the end.
Also you are underestimating the power of bull run vortex on crypto speculators. Crypto speculators tend to dive headfirst into opportunities to make a quick 300% gain.
ETH has no future because Vitalik proved the blockchain can't be trusted. If we want blockchains to remain immutable, ETC must win. I think Bitcoin supporters will make sure ETC wins against ETH.
I think the DAO benefactor hacker is likely profiting big time on leveraged ETH shorts, while being leveraged long on ETC. So he can use proceeds to drive the price the direction he wants, while never needing to actually cash out of ETC.
Bitcoin investors would love to see ETC kill ETH. And if they can make money doing that, then it is a nobrainer.
But there is an equivalent number of ETC in the Ethereum foundation's premine of ETH. Don't you think Vitalik will once again make a desperate move to save the fork by dumping all the ETC they can potentially have and buy ETH with it?
My estimated guess is he is naive but not that dumb (to think he can fight the market with certainty). Remember he did diversify and sold 25% of his ETH, having learned from holding BTC all the way down in 2014/5.
And if he does, then it will just be Vitalik destroying himself at the end, while the other fools have one more chance to sell ETH to Vitalik so he is left holding the bag.
That is unless Vitalik can work some of his mesmerizing magic with his words, somehow deluding a large swath of people that he can create something for ETH that would justify the loss of immutability trustlessness of the blockchain. I don't think he can any more. He has played that card already. ETC can copy any open source improvements worth having. Some mETH heads might be thinking Ethereum is leaderless if Vitalik loses this battle, but I don't think ETC investors care. Speculators want to make a buck and if they can enforce correct ideology as well, all for the better. Perhaps some fresh opportunities for others to contribute on the concept of smart blockchains might spawn some new innovation that Vitalik et al didn't accomplish in 2 years. They were given $millions to play with and so it isn't like they didn't get theirs or weren't given every opportunity to perform.
I am hoping Vitalik will capitulate and join ETC and in more of a subservient (as in serving and honorable) role to the community. That would be the best outcome I think. The correct ideology would win, Vitalik would grow up, etc..
P.S. I am assuming the financial back of the price manipulator behind ETH will be broken. If that is not the case, then I guess we could ride a yoyo seesaw. I think perhaps this manipulator is hedging his options.