Currently on the coinmarketcap site only about 1590 projects compared to at times more than 1700 projects. They have left many projects without developers or scam projects. I personally invested in some of these projects and lost a lot of money like bitconect and centra. Do you trust the projects you are investing in and will keep them for a long time until they succeed or are they just looking for profit in the short term?
Obviously, some of these projects loose traction over a while, Developers zeal die off or maybe an orchestrated scam. Recently, I read that Okex have provided a list of coins to delist before first weekend of December. That is why it is important to do thorough research on any projects while factoring sustainability before it investments