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?
There are projects that aren't just profitable anymore and some are just down right useless that's why some exchanges just drop them because they are a nuisance in the whole market. They make more space for upcoming high potential and much more profitable tokens in the future.