this may due to two reasons:
The first reason is that the coin or token has no real value.
The second reason is the large sale of those who got his coin free such as airdrop.
Isn't that true?
because as soon as the hype ends, there is nothing stays and most of the holders and investors are aimed to sell out as soon as possible after the hype ends. it is always like this both in icos and ieos
Investors who bought just to sell quickly are irresponsible and inexperienced people. Every good investor knows that the money invested in strtup pays for itself within a few months at the earliest. If someone only looked at market behavior, not project development, he definitely lost. It is because of such irresponsible investors that the price drops right after listing on the exchange.