>Or was the parity wallet multi-sig attack something that most lay-people knew about as a risk before it happened?
IMO that's more of a problem with smart contracts than with cryptocurrencies as a whole. if you allow anyone to write code that controls millions of dollars, there's going to be ten different implementations and a hack in one of them is virtually guaranteed. on the other hand if the multisig mechanism is part of the network protocol, there's only 1 implementation which will be better scrutinized. even if there was a bug, at least the intention is clearly conveyed and can be fixed with a non-controversial hard fork. see: bitcoin's block reward integer underflow hack vs ethereum's DAO hack.
IMO that's more of a problem with smart contracts than with cryptocurrencies as a whole. if you allow anyone to write code that controls millions of dollars, there's going to be ten different implementations and a hack in one of them is virtually guaranteed. on the other hand if the multisig mechanism is part of the network protocol, there's only 1 implementation which will be better scrutinized. even if there was a bug, at least the intention is clearly conveyed and can be fixed with a non-controversial hard fork. see: bitcoin's block reward integer underflow hack vs ethereum's DAO hack.