Of course, the coin should have an idea and perspective. There are a lot of coin projects which will disappear in a short time and their coins will no longer be worth anything.
It depends! As long as someone is running a node or has a copy of the blockchain, no coin is finally dead so to speak.
But you understand that so many projects that issued their coins in the future will not be worth anything. It is even possible to look at CMC. Even those coins that were in the top 50 in 2016 now do not exist
Anyone remember Paycoin (XPY). I was unable to remember its name.
I searched my hard-disk to find the screenshot of Cryptsy balance. After finding the screenshot, I recall its name.
In 2015 it was about $10 USD (when BTC was $300-$350 USD).
Now, it has no value (0.00000299 BTC). But, it's still alive.

It is useless being alive.
Unfortunately we will all meet such tokens. It is very important to choose the coins for your portfolio and not to invest all your money in a single project.