The comparison with oil and gold is a wonderful epitome for these two coins, did you come up with it yourself? I would put it in a frame if I could.
And, I agree - ETH has some problems to work around, otherwise, other big coins can take their place in the long run.
Yes. I came up with it, after analyzing the use cases between both cryptocurrencies. ETH is like "Oil" or the "Fuel of the Internet" since it's required for the deployment and execution of smart contracts (otherwise known as decentralized applications). Without ETH, people can't interact with dApps native on the Ethereum blockchain. This is the future of the Internet. That's why they call it "Web 3.0", right?
In the case of Bitcoin, its meant to be used as a store of value. You can also use it as currency if you like. But sudden high network fees and market price volatility, greatly defeats this purpose. BTC is more suitable as "Digital Gold" than "Digital Cash". Whenever you want to protect yourself against inflation, Bitcoin is the answer. Both cryptocurrencies are extremely-useful and different from one another. I'd expect BTC to remain the #1 cryptocurrency in the world forever. It's the one coin that started it all. Hope to see ETH rise in mainstream adoption soon.

Great points made.
Did you see Vitalik's performance on Token2049? Nothing special, even a bit cringey, I would say, but he at least called for Decentralization for all the structure of ETH. Can't say if it was for the sake of it or for real developments in the future.