I recently read an analysis article, which stated that IEOs are being profitable for early round investors. And it was backed by sufficient amount of numbers.
However, only a dozen IEOs were chosen for the analyses and I am not convinced that throwing money left and right in IEOs is a good strategy right now.
Now matter if we are talking about IEOs, ICOs or STOs... there isn't interest in altcoins right now on the macro level.