It's difficult to give a percentage. I'd rather talk about classes of crypto assets than individual coins or what percentage of them could survive. A lot of projects that are small-cap may simply run out of money and be forced to call it quits.
I see future potential in security tokens and utility tokens.
Security tokens are tokens that represent right of ownership of securities such as bonds, stock, options or any such assets classified as securities. Security tokens have an underlying asset backing their value. They are essentially a method to add to the liquidity of highly illiliquid assets such as real estate (high-end in particular) or works of art. When an asset like that is wholly or partly tokenized, it will be easy to sell small parts of it. That would make funding large projects that tie up a lot of capital easier. For example, a shipyard could tokenize a vessel under construction and gather funding for it from retail investors without any paperwork required of the investor. Of course, such tokens would have to be issued by reputable exchanges in stable jurisdictions to be trustworthy.
Utility tokens are another class of tokens that represent an underlying asset. In case of STEEM, it is the the right of access to network resources, witness voting and voting over the reward pool use. A utility token could represent any resource such as power in a decentralized electrical power grid where there is local generation and consumers who act both as producers and consumers of electricity.
From what I have been reading there are only a small percentage and realistically there may only be a handful of crypto currencies that will have an every day use.
I think that this may be a bit harsh as i have seen a list of around 10 that experts believe will make it and be around in the future. There are literally thousands and more being introduced from new ICO's but if I had to have a guess I would say less than 50 and maybe closer to 20.
most of the crypto currencies are pure speculation and a huge gamble as they haven't proven anything yet. I think this was the reason behind the surveys done by the Japanese and Chinese recently to see which ones had a use. It was a simple ranking and if I am not mistaken Bitcoin was ranked at 18. Steem was in the top 5 of both lists which is good news for all of us.
It's hard to make such a prediction, but given where crypto is today, I would say perhaps 10 percent will make it in the long run.
I think certain crypto's are going to surprise people and certain crypto's will be the stories of major disappointment.
I'm pretty confident Steem will not be failure. I mean seriously, I don't care about any other crypto's at this point, because Steem has a very real, practical use. I take stake out to day trade, I lose profit on curation. I enjoy the process of growing my Steem power.
I've encountered so much bombardment regarding day trading, and people trying to convince me to partake. I won't do it. I used to, and I ended up losing. Perhaps day trading isn't for me. I'm more of a long term hodler. I like all my crypto in Steem, and that is that.