My short discussion is that the most profitable trend among them was ico and it alone brought new projects to the crypto market with 2017 and it was very popular with everyone. But then the IEO started and when the amount of scam projects increased again the IDO started again. However which one do you prefer?
As a matter of facts, the most profitable sources of raising funds then was ICOs but currently, I doubt ICOs are any longer profitable. Firstly, many ICOd this days that were successful no longer list coin/token above ICOs prices and token the distributions are carried out in small percentage that you can hardly make profit when coin is listed. Again, I think ICOs are not profitable, though there are many that are characterised with scams, and many ICO processes has become unclear to investors.
Further more, I think that IEOs are more profitable in all fund raising processes especially on the bigger CEX exchanges like Binance, Kucoin, Bybit IEOs etc.