All these ICOs became successful only after a major investment and with a successful development and a good idea.
That's the real basis but development just came after the team raised the necessary amount.
Project which raised a big amount of money is not also a guarantee that they will be successful, that still defends on the market situation and how the team would handle the project, actually last bull run the ICO was so profitable, if they know how to manage the risk, they should convert their ETH raised to fiat for the future development of the project and volatility would not affect the project.