Why did dYdX leave Ethereum?

Could you elaborate on the reasons behind dYdX's decision to leave Ethereum? Was it due to scalability issues, high transaction fees, or perhaps a shift in strategic direction? Did they encounter any specific challenges or limitations that led to this move? Was it a conscious effort to diversify and reduce reliance on a single blockchain? And finally, how do you believe this transition will affect both Ethereum and dYdX in the long run? Clarifying these aspects would provide valuable insights into the decision-making process behind this notable industry move.