The rate at which new coins and tokens are issued, many of which are purporting to solve the same problems in the same ways, means that quite rightly, the vast majority are viewed as speculative at best and downright scams at worst. Many people will have been burned by ICOs in 2017. I hope people are more healthily sceptical in 2018. The technology of blockchain and related tech will be here in the future, of that I'm sure, but which of the current batch of big hitters will be long term, or even if the ones which fly haven't been developed yet, I cannot say. I would say that I'd steer clear of coins who's value is based on huge social media communities of fanboys who trumpet every small step as seismic change eg. XVG being the first crypto accepted by Pornhub.