The price of cryptocurrencies basically follows the rules of demand and supply. As the coin becomes scares it becomes more valuable and hence the price increases. One common mistake most investors do is that, once they see the price of a coin is going down, they hastily dump what they also holding which increases the supply more than the demand and further reduces the value of that particular coin. Later we try to put the blame on the team that they are not managing the project well. Let's help sustain our coins by avoiding panic selling. Its a collaborative effort.
It's actually the returns of the project that makes the price of token move. You would get no benefit from holding a dying coin. And waiting a dead coin to resurrect for 10 years is not a good idea either. The first thing we should do is choose what we are going to invest in. A good investment would never let you down.
It can't be prevented. In fact that those people are holding so many funds can do whatever they want to the market. The return of the projects depends on the how much the price of token itself after it was being calculated with the how many bonus they will be received from the ico team. It's so difficult to choose the best investment.