Because the entire crypto ecosystem is running on Ethereum. Coins that have millions of users BAT, DENT or that transact more than 100M million in dollars NEXO, DAI are running on Ethereum.
Also, the entire DeFi landscape is running on Ethereum with already more than $670M (!!!!) locked up and this is a very slow market. Imagine what happens when the market picks up again.
Bitcoin has nothing against that, look at the tiny Lightning Network with a measly $6.1M.
Bitcoin only has the first mover advantage and is resting on its laurels doing nothing while Ethereum is the hardworking newcomer that is better than Bitcoin in every way by the factor of 10. With ETH 2.0, it will be better than Bitcoin in every way by the factor of 1,000.
Ethereum will launch ETH 2.0 with PoS and Sharding in 2020/2021, at which point they can scale infinitely and have no restrictions in terms of transaction per second since with Sharding their blockchain becomes more scalable with each new node added.
The anticipation of this new technology can bring Ethereum past $1,500 by itself.
Furthermore, Bitcoin is very likely to break its previous ATH of $20,000 as well in 2020 due to the Halving.
We’ve already seen how in June this year it went from $3,100 within 2 months effortlessly without a care in the world.
This is VERY likely to repeat this year again.
It is also possible that Ethereum will replace Bitcoin as the #1 coin in market cap in 2021. This has already almost happened in 2017.
Now, Ethereum has improved a hundredfold in terms of usage, money locked up while Bitcoin hasn’t changed much.
Big times are ahead for Ethereum.