Those coins were not getting the volume can't attract the buyers. If you are seeing from here
https://coinmarketcap.com/new/ and then you will see some new coins have a very small volume.
That is a thing to happen. It never makes sense being listed if there is no volume, definitely, investors would have no time to take a look at them but just have to ignore.
This is happening almost all the time, some developers make it just to show that they are legit and just to fulfill their promise with the early investors but I'd never think it was enough. The legitimacy of a certain project will not just be listed but it should have a market volume, it is proof that there are people do buy and sell, not a dead one with ZERO trading volume.