Getting on a decent exchange is still going to help with marketing and getting the word out, one of the stated objectives. Not only that, but it is, or should be, an obligation to the investors to provide them with a good option for liquidating their investment should they choose it is no longer for them or if personal situation calls for it.
Liquidation is not an obligation. Have a look at Tezos for example. They have no buy-back plans and wont be on an exchange for 4 months minimum.
Investment in an ICO is a long process. Just because some have allowed pumping and dumping this should not be the model