One can not say with full confidence that most crypto currencies will collapse to zero, as today more and more teams that create new crypto-currencies take on the staff of professionals who make a good idea a successful project.
That's right. Many have claimed that this would happen over the past several years and months, and up to now, even if some market assets have really died out, many are still left, with some new comer coins adding to the market every day. With that being said, I think that the market is continuously evolving and is adding up more assets that would help it prosper, so saying that many cryptocurrencies would go to zero has a reality to it, but only for those that doesn't have a chance of prospering in the market.