Pretty soon, initial coin offerings are going to phase out completely.
Pretty sure OP meant offerings in general, meaning investing in new projects as a whole, since IEOs were not as popular in 2018 he just preferred to use the word ICO.
Now in 2021 many things have changed and we got IDOs and IFOs as well which in this bull market can give you a very good return, and that's of course if you done your research and they have at least a decent project plan and are not scams/rugs, rugs are are only problem of this bull market since DeFi tokens are very popular now which mostly have anonymous team and even though sometimes code audits could give investors some assurance, there's no guarantee the auditors did not miss something which could result in that asset going to zero in just one hour or even less.