At the moment it’s unclear whether there were actually successful double spends as a result of this attack: https://ethereumworldnews.com/ethereum-classic-etc-developers-2019/
Will be interesting to monitor. My sense is that exchanges have underpriced the cost of listing PoW forks with low-$ chain security
True, although it seems like it wouldn’t be hard for exchanges to automatically detect deep forks and halt processing of deposits/withdrawals for that network. Would be very hard for attackers to prevent the exchange from detecting the fork, unless it’s a targeted attack against a different exchange, so this mechanism would be a solid defense.
I’m curious if events like this will ever result in the price of the coin actually dumping. If exchanges halt deposits/withdrawals during a 51% attack, a whale could pump on a single exchange without worrying about getting dumped on by arb bots