if the price falls after the ICO - it`s not mean that project not popular. It`s may be because now bitcoin price fall down, and many people afraid buy crypto - and tokens of this project too.
That's normal because most project falls after the ICO but it's temporary that's why smart investors
are also taking this opportunity to buy cheap coins as they believe once it will be listed in bigger exchanges that price could rise easily
and this would give them easy money.
Been doing this method and it really works for me.
Normally, investors put aside a half of the budget for ICO in order to purchase the token after ICO ended. As the price of token mostly drop afterward, they can own more tokens than spend that fixed budget totally in ICO.