No, not all of them. There are useless ones and they should be taken out to clean up the crypto technology.
Try to visit Yobit and you will see a lot of coins which have 0 value but some people can resurrect them and will victim a newbie if ever he will invest in it.
They will just use the chatbox and it will look like different people are investing but the truth is they are just one group who is scamming another.
They should be cleaned to avoid new investors to be another victim.
Unuseful coins will die for sure. Some coins are used only to scam investors.
There are also many abandoned coins that are used only for pump and dump. Curious newbies with FOMO buy that coins and at the end they have bag full of shitcoins.