Or will they feed off of Bitcoin's carcass and take off?
This is not possible, and if the bitcoin bubble bursts, the entire cryptocurrency market will collapse.
there will be a chaos in every place because of many people right now depend on cryptocurrency to make money and I guess they will become angry and cannot think of clear. the altcoin will become crash too if bitcoin crash but I think there will a new solution for cryptocurrency to survive because cryptocurrency offers something different and it is a new technology that will grow in the future and maybe we are using the cryptocurrency for daily.