ICOs & IEOs are same in my opinion so we can say ICO are not dead but it got upgraded to IEO with only difference is IEO offers confirmed listing on the exchange on which project held fundraising. Check this report https://cointelegraph.com/news/bitmex-crypto-ieo-poor-performance-sees-investors-lose-up-to-98. If you want to invest in IEOs still you have to do research like we used to do for ICOs like team background, Concept of the project, revenue generation, token matrix, advisers, partnership, working product, user base etc.