Certain ICO's in the past have shown to be very popular and profitable, making a proliferation of new ICO's trying to get in on the pie inevitable. That said though, many investors look for clear signs of game-wining ideas to be present before they invest, this most-likely being especially true for big investors who have knowledge from past investments. While it may be easy to make a Coin on the Ethereum network, I would hope that knowledgeable investors in the crypto space would be aware of clear signs of a product made just to go along the wave but does not have any real value, and shift the market accordingly. ICO's have a lot of potential to be the basis for ground-breaking technologies, but as you insinuated, not every good idea ICO will survive, as was evident in the dotcom bubble.