There are many reasons behind the crash of the ico thats why the investors got tired, the reason is that most of the investors, especially the big investors, turns out that they make money in ico for a living. So when the ico got in the first exchange it is totally crashed due to many investors dump their coins.
As you said we have many reasons why icos are not trending again.
Scam ICO filled the crypto space recently, even after good reviews from reputable review site, some projects still turn out to be scam, this makes investors to be weary.
In a way SEC clamp on some illegitimate ICO is bringing a control to ICOs, because it's already getting out of hand, you can imagine how many ICOs is launching on Ethereum blockchain every day.
ICO projects really needs to go back to good and real use case not just an avenue to make money.