If ICO wasnt been plague by scammers acts ICO will way better than IEO, ICOs are programmed to run on the projects very own website and no any third party involvement at all so any fund raised will go directly to the dev or project team, no loss of funds to scam exchanges,after some successful IEO fund raise on some exchanges they dont bother to send the funds back to the project teams
Where there is money, there are scams involved. And sometimes differentiating the project to be a legit or scam becomes difficult. There are several reasons why investors call a project scam. And several other scams which doesn't get a scam tag from the investors, at least until it's profitable. So, it's also the lack of research from investors and thoughtless investments that are boosting the profit and morale of scammers and are making it a lucrative market for them.