many developers are not interested in creating a long lasting project out of their coin, and there are many reasons for this, like being to difficult, being unable to do so and too much competition, so as soon as they gather enough funds then they decide to just forget about the project, but in order to not look like complete scammers they simply delay their exit and make it seem as if the project just died naturally, even if they were the ones to kill it so they could just move on and create yet another coin or begin to spend their ill gained profits.
It's easy to trace or find them when they tell potential investors that they are the meme or Doge killer or they are a fork of this coin and they are a better version, expect their coin to live on hype, a coin that draws its strength from other coins are useless and shitcoins, we have seen it in the so many Bitcoin fork in the past which they are a better version of the original Cryptocurrency.