What is the price at which a coin is considered dead or when an exchange decides to delist the coin?
Like bitcoin was 20k in jan so if it reaches less than 1k we can consider it dead?
For me, if the project is not active anymore that the developers of the project are not active anymore, no more commits on their github repository, just like that and the volume of their project is very low like it's down almost 80% of their ATH. You can also consider their social media accounts if they are still active.
At least that's a reasonable reason mate, when developers are no longer active in spreading and updating their coins, they don't make improvements when the price of their coin goes down, and there isn't any response, it's very likely that the coin will die, because the key of coin to be alive is user trust