true. but not everyone that participates in ICOs knows how to enter in the contract address at a dex to find out if the tokens are being sold cheaper.
I think most of them know. Maybe only private investors don't know and right now only Money are coming from them.
maybe in 2017 the ico have been really overestimated and their real value is current value, perhaps the future of ico is fundraising based only on private investors who have great availability of funds and do not watch the prices of dex...