Always have a benefit of the doubt, only the top 5 coins in the market deserves our trust other coins are still struggling, they can still fail and leave the project, if you invested on these kind of coins always get an update and news about their progress and if there's a hint that they are changing direction then by all means leave the project, do not have attachment to these kind of projects.
Those were the famous last words of coins like Bitconnect and Onecoin, though! They were for a very long time in Top 3 by marketcap, so I would say let's not jump to conclusions just because of capitalization random rankings.
Just look at Bitcoin and Ethereum, and the seriousness their users and developers have, actual economies, not vaporware.