Ethereum still has a long way to go compared to bitcoin but I'm not just saying this based on the current price differences but also based on other factors. Bitcoin has been widely adopted by so many institutions unlike Ethereum, the investment rate is also higher for Bitcoin, but first of all Ethereum would have to surpass Bitcoin in total market cap for there to be a comparison at least.
I wouldn't say the cap is the issue, the issues with the chain are more about it - for the projects and users alike
The cap is just the fact that BTC is the digital gold, whereas ETH has more cases and vibrant ecos - so it's the fuel for them, digital fuel.