Yes, you are right the successful IEO's are from the potential exchanges like Binance, Kucoin, Bittrex, Okex etc. Of course, IEO's already listed on those exchange cannot able to increase their value but only from the Binance those coins has given very good profit to the investors.
Let us not presume that any IEO that comes from Binance will always give profit to investors in short term as it's not true.
Some people doesn't know the real IEO success rate of Binance when they see one project successful they tend to think that all the projects will be a success and that's why the hype starts.
Common mistake on most people where they do generalize all things on just basing on a single project that had shoot up its price and succeed.
Hype does really built up on that one and neglecting or doesnt focused out on other projects that doesnt give out benefits into its investors.
People are way too direct when making up conclusions and when the hype is already built then it do give out that domino effect until the entire
community will able to believe that ieo investments are 100% profitable which isnt really what it is.