Ethereum, being the world's second largest cryptocurrency by market cap, has all the potential of replacing Bitcoin in the future. It's more than just a cryptocurrency, being a platform for the development and execution of smart contracts (aka dApps). With ETH, it's possible to launch alternative cryptocurrencies without the need to start a Blockchain from scratch. It's also possible to use the ETH blockchain for other purposes such as voting, proof of identity, verification of documents, and more. In contrast, Bitcoin's only use is for finance where it cannot be implemented in other areas by its own.
Given all of the benefits Ethereum provides on top of Bitcoin, it makes me wonder whenever it'll be able to replace the pioneer cryptocurrency within the future? As long as, Ethereum keeps progressing in development and mainstream acceptance, it'll be much closer to Bitcoin every step of the way. What are your thoughts?

Only the future can tell, any coin with great developers and active community can make it on the top of the market, Ethereum has a good chance, it's easy to tell imagine a market without Ethereum smart contract, they will not know that transactions can be in seconds and the fee is very small, Ethereum also attract a lot of people in the Cryptocurrency, not only Bitcoin.