Many cryptocurrencies are available in the market for scamming users. They often run multiple presale events and, once they receive investments, they disappear with people's money. Then, they start a new project under a different name to scam again. These actions are unfair to crypto users.
Unfortunately, it cannot be controlled because it is like bubbles that constantly appear and disappear. Personally, I believe that the real numbers are greater than those mentioned in the analyzes in OP because the current number of projects listed on Coingecko includes SCAM projects whose failure has not yet been revealed.
This raises the issue of the conditions that platforms impose on projects to list their currencies on them. All scam projects would not have succeeded in scamming users' money if they had not found trading platforms that would accept their listing.