the first thing about price is coming from its supply and demand and that is true for literary anything in the world. from a loaf of bread to the most expensive things on earth.

now bitcoin has only 16 million coins available and will have 21 million after a long long time. and all this time it has gathered a lot of deamand. even big countries are accepting it as a legal way of payment. aka a currency. now bitcoin with this supply and this ever growing demand is barely worth $1600

now lets talk about ethereum. it already has nearly 92 million coins available and it has no maximum amount. until the end of this year it will probably have 150 million coins and growing. the demand however has always been restricted to two things:
1. traders buying it on exchanges. to dump later on.
2. newbies who are looking for profit buying ETH to invest in a scam ICO
both of these demands have an expiration date. and with this supply and this dwindling demand prices can only drop.

in short you can only dream about $1500 for eth