If bitcoin won`t be the main currency use in crypto exchange then ETH might have a good chance of becoming number 1 but in the current situation, it is not possible for a very long time.
It is unlikely that Bitcoin will ever give its place to any alts, it seems to me that we will never see another coin on the 1st place in the market, investors like to invest in Bitcoin and therefore no one will take its place.
You are right, every altcoin price is based on the price of Bitcoin, reaching to the first position is not an easy job for ETH, look at the market cap for Bitcoin, it is more than 61% dominance compared to all other potential coins. It is impossible for ETH to secure the position of Bitcoin.