I'm not really sure about what really the cause of the drop on the coin price when it got listed in the market, but what i think, that would be because there are people who sell their coins in a lower price compared to the price when it firstly introduced during the ICO or something like that. because those people wanted to have quick money from the coins that they had. That is what i'm thinking of.
that's because the coin market has not yet been formed. most are people who come from the coin community. and they all want to sell to earn money. the disadvantage for the new project are listed, it is because the team has not been prepared or not growing the trader to make a strong buying power in the market. When the response of the market is still less then that happens those who sell will surely lower the selling price.