The next 5 or so years is going to be pivotal period for the major cryptocurrencies that have already established themselves in the market. I'm not talking about the new projects that have just been formed or those projects which are researching solutions that will only come to fruition many years from now. I'm talking about Ethereum and Ripple - projects that have already established their research roadmap and are well on the way of following through on their business strategy and making their respective solutions a mainstay in their respective niches.
We're nearing 2020 and I think there has been some agreement among traditional financial entities that blockchain, if not cryptocurrencies themselves (though they are an integral part of decentralized distributed systems), will find a place in existing industries.
Which projects among the many in top 20 or so will last into the next decade? Some of them directly compete, like Ripple and Stellar for cross-border payments. So do Ethereum and EOS. When I say "Can Ripple and Ethereum co-exist?", I don't mean they're competing with each other, I mean "can one of the big names that we know to be popular now survive into the near future?" We assume that these projects' applications and adoption will take off but there really is no way to know for sure.
In my opinion, they will and there's good reason to believe so. They are both working on two very different purposes - Ethereum as a decentralized world computer and Ripple as a means to save and speed up cross-border payments, among other banking solutions.
Both have done well to establish a large network of partners, enterprise players and stakeholders across very segments to ensure that when a product is released, it is tested and developed on. Hell, Microsoft is even actively encouraging Ethereum development, having released an Ethereum development toolkit with its Azure platform. Ripple on the other hand is cozying up to some of the financial world's biggest players at events all over the world.
More than the technical solutions that are being developed, I think it is in the slow and steady persuasion of incumbent entities where the possibilities of both projects lie. Blockchain and cryptocurrencies deserve scrutiny (perhaps not in the harsh light that some mainstream business outlets view it) but it must be rational scrutiny. By working with established entities and building solutions for them specifically, these projects have the capacity to establish a deep fundamental need for blockchain for several industries. And Ethereum, with its smart contracts, and Ripple, with its speedy payments, are projects with solutions that make said adoption an easy sell.