What dead crypto currencies do you know?
What are the possibilities for crypto currencies that almost can't be exchanged any more?
Do you have any ideas how to make money on big amounts of abandoned cryptos?
If one have good plan for advertising campaign, he can possibly "revive" a dead coin. Of course aside from popularity, if the crypto is truly useful and relevant right now, other people will catch up on its potential train. It will be difficult but it is not impossible to "revive" a dead coin. It can also work but it can also burn bright and short lived too.
I think it will be more difficult to revive a dead coin, because there are already many investors who do not believe it, of course it takes extra promotion. therefore many developers choose to make a new project again.