ETH will never be a BTC cause ETH is just limited than the BTC, where BTC is still in mining. And ETH depends on the value of BTC.
Who limit the potential of ETH? Both BTC and ETH are into ongoing mining for their supplies but most probably the latter will stop and will shift into staking which I think is a good idea as it is more environment friendly.
Most coins in the crypto market are dominated by BTC but one day many of them especially the solid ones will become independent and move on their own and ETH is the leading coin to do that.