Well - Bitcoin is the first. That probably means it will always be the first choice. But ETH has achieved some of the goals of Bitcoin that Bitcoin, because it is the first, has been slow to adopt. They are both successful for similar reasons, because they continue to have people use them as foundation tools. They built exchanges on Bitcoin and tokens on ETH.
Yes that is also right. People are mostly giving more importance to these two cryto currencies. Most of the people and projects are using Etherium for token system. while they also use bitcoin for transaction of fund or selling something. In future i think these two cryto currencies have good potential and people will continue using bitcoin for long long time.