Some of you mentioned that a coin is dead when the dev lefts the project. The truth is that in the last few months this isn't really an issue since the altcoins aren't used for their original purposes. I mean most of the people on exchanges doesn't even download the wallet or withdraw. Especially the coins which don't have a real purpose.Even "dead" coins are pumped on a daily basis on different exchanges. You can see a lot of 1 sat coins being pumped to 5-10 sat.
when the dev left the project, the project is dead, but some people will still be playing with until the trade volume goes close to zero and got delisted on exchanges, with no price value attached to it.