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.
The development in cryptocurrencies where developers can use the network of other coins to create tokens has resulted in many projects appearing because the manufacturing costs are easier and although they have roadmaps and whitepapers, most of them are just copies of existing projects and many of these projects have no use case so they are only created to cheat.
Investors remain interested because they also see the opportunity to make quick and big profits.
50% is a very large amount and if the consideration is how the coin/token has experienced a price decline then the percentage will be much higher because we see that many coins have fallen by 99% in price and it is impossible for them to rise to their initial price so this can be said to be a dead coin and a failed project.