firstly. the linkage of the movements of the bitcoin and ethereum market are clear that ethereums market is shadowing bitcoin. because bitcoin has known market cycles and if ethereum was independent it would not be following bitcoins market cycles. so when it does follow bitcoins market cycles, its obvious that its ethereum that is the follower
That's a great point.
ETH would not profit from attacking bitcoin because:
1. It would have to allocate tremendous resources into that and it would not destroy the network. All it would do is prove that with enough effort it can be done, but we all know it can be done and we all know it such attack cannot be sustained. It's like a DDOS on the whole country. You could do it and cut a country from the Internet for a while, but how much it would cost you and how long would you be able to sustain it?
2. A panic on the bitcoin market would most likely cause a panic on all other coins. If this attack was only to buy more of everything, that might work, but it would not make people flock from one coin to the other. The whole crypto industry is a big ecosystem.
3. What do you thing would happen if bitcoiners found out Vitalik and team are behind the attack? He'd climb above SBF and CSW to become the most hated person in the industry.