I don't think the market is irrational between BTC and ETH, except perhaps that ETH is valued too high. They're for different purposes, although ether can be transacted in a way similar to Bitcoin. Think for long term--what is worth more in the future relative to today's price? Bitcoin may very well become a reserve currency of nations and individuals. If it achieves this, it'll be worth more than $500,000 per Bitcoin. Ethereum may very well become a decentralized world computer. Question is, does the value of ether need to be high for it to become this? Additionally, which has a riskier roadmap for development of its technology and will speed bumps derail its progress? To this latter question, I'd say that ethereum has way more risk inherent in its development, particularly because Bitcoin could, for the sake of argument, not change ever again and it would still exist and fulfill its intended function, which is to store and transfer value. Also, keep in mind what drove the price of ether higher: the ICO craze. Ethereum is not being used for anything beyond speculation and feeding token creators. Furthermore, ICOs hold a lot of ether and many haven't even begun burning much of it or unloading it, at least at the velocity that they'll reach if they ever launch a product. I'd say Bitcoin is more likely to go up by a non-trivial amount at this time than ether.