That's always the norm in crypto land. Some altcoins will fall, while others rise over time. When put up to the test, most altcoins cannot achieve true reliability and security. This is mostly because, developers in charge of these projects don't actively address issues, and instead they're only interested in making money out of them. However, altcoin projects with a long-term vision on making themselves useful for the mainstream world will most likely survive in the future.

As such, it's not about hype, but true development and innovation. Many altcoins have claimed to be superior from one another, but they haven't proved their claims with their technical features. One good example of this is Verge, which claimed itself to be a true privacy coin, when in fact it's not. It was mostly driven by hype. Considering how it's been attacked by the same issue without being properly addressed by its developers, means that the altcoin will die anytime soon. However, there are a few altcoins which are constantly being developed and maintained by their communities. They've been able to provide real uses for the mainstream world, and their technology has been tried and tested over time.

Altcoins such as: Ethereum, NEO, EOS, Waves, Dash, NEM, and Cardano would most likely survive in the future because of said reasons. There is nowhere else to look for, since these cryptocurrencies have a solid foundation built upon them delivering security, stability, and reliability to everyday payments. Since most of these projects are smart contract platforms, they could provide functionalities way beyond finance.

Nevertheless, while there will be a few altcoins which will survive in the future, it cannot be known for certain which project will remain in the crypto space since crypto land is fully unpredictable. Just my thoughts