There are 2 giant blockchains we are looking at, the Bitcoin Blockchain and the Ethereum Blockchain. We would like to see how each of them is of value to the community.
Ethereum Blockchain.
It is a decentralized platform with purposes and features which include applications and a decentralized payment system. Another use of feature of ethereum blockchain you can use it to write computer codes including smart contracts.
It is based on protocol of Bitcoin but its design is meant to support applications not just payment systems.
Bitcoin Blockchain.
It is a decentralized platform which serves the purpose of a currency and it is a public ledger which keeps records of block transactions. Its a peer to peer and people can transact freely.

Will Ethereum overtake Bitcoin?
Depending on the factors to consider, bitcoin right now dominates the market when it comes to currency and i don't thing Ethereum will surpass it any time soon. If we are to look at the services offered by these 2 different blockchain then Ethereum is far much ahead. Its platform support application, other crypto tokens, smart contracts and currency as-well.
Coin Supply - The coin supply of bitcoin is much lower than Ethereum
Liquidity - Bitcoin is more liquid as compared to Ethereum
Technology - Ethereum is technologically advanced than bitcoin which makes it better on that factor
With all these factors in mind when it comes to currency and liquidity bitcoin will be the way to go but if it is about technological factors, smart contracts, application then Ethereum is the way to go. Both blockchains are great and serves different purposes.