I do not think that this is related to the exchanges. Actually price is not affected by exchanges generally rather price is determined by the demand of the projects in the market. So if the demand of the ICO is low then the price will be low also.
However, exchanges do play a role in crypto–currencies prices/values. A rumor of a low–cap, low–volume coin/token getting listed on a rather large exchange could send its price flying. A piece of an article about *insert known exchange name* getting hacked and losing millions in the process could plummet certain coins' prices. A large exchange with huge investments could make even the most worthless Altcoins worth some value, and could be the end of others as well.
On-topic, I do think the same. So far, I haven't seen any decentralised exchange solve its own problems or any of centralised ones. They are complex (to new, average users), slow (expect 'We are being DDoS–ed' announcement/tweet all the time), unresponsive, still hack–able (due to 'hot wallets'), involve doing a lot of actions, have hard–to–digest User Interface, and mismatched trade orders is a common issue, and many others. All that drive people, who aren't concerned about privacy, security, etc. (i.e., majority of people), away to simple exchanges/ICO platforms where you can trade and invest with a single click (read: Coin Factory, Cryptonomos, Coinbase, Binance, Bittrex, etc.).
