Whether or not some other coin will dethrone Bitcoin will depend on its immediate utility and usability and not on possible use cases or technological superiority. Until smart contracts become practical to use for both common people to use, common people to trust, and scale to the demands of common people, I don't see anything coming "sustainably" close to Bitcoin in the next ten years. Bitcoin has probably the most secure network that relies on little trust on governance and the exterior community. This makes the base protocol layer extremely resistant to change (which can be seen as a good or bad thing). But there are tons of blockchain developers working on scalable solutions to both money transactions and introducing smart contract capabilities onto the Bitcoin network. Perhaps, Bitcoin doesn't need to be the blockchain that doesn't everything. But rather Bitcoin provides a less variable slow changing layer one foundation for other sidechains, blockchains, and protocols to build from. Being a source of secure randomness is a benefit that you mention that can be applied in lots of ways that are useful. Other blockchains have risen up due to weaknesses in Bitcoin's protocol. I only wonder which side of development will win out? Those building on top of Bitcoin to fix its weaknesses, or those starting from scratch that solve these issues while compromising in other areas like security, centralization, etc.