The main purpose of investing is to expect something in return later on. People invested on ICO's because no doubt that it will really give an interesting return in the future. Any investments is risky that's why if you not understand how ICO projects goes well then better not to invest.
Will ICO's be here actively all the time ? Well as long as crypto world is showing good support from the community, there will be more ICO's around that will popped out every now and then.
Exactly! Like any other investment, when the price of an investment hit its low, some people see risk and lost, others see future gain and opportunity. Since high risk often comes with high return, I would suggest you ask yourself whether you have the financial freedom or the kind of personality to join the crypto game.