I doubt ETH will surpass BTC longterm. People want a safe place to PARK their wealth and Bitcoin is ideal for this. Who cares how many transactions something has?? I don't own Bitcoin so I can buy a cup of coffee I hold it because it is a safe haven asset with scarcity.
Don't get me wrong, I love ETH as much as the next person but it will mainly be used for smart contracts and transactions.
Time will tell.