I find that 2018 and 2019 is just heavily moving away from the open public ico's and seems to have a huge shift toward institutional and private sales which i think is good for the project but really does shrink the chances for the small guys getting into big projects at good rates early
I personally don't see ICO's as a valid investment that should be eagerly taken. Most projects have left investors worst off and in my opinion one should be very careful about choosing an ICO to patronise. It's an obvious fact that most projects get listed far below the ICO price.
But the fact that most tokens are now trading below ICO price has a lot to do with how the crypto market performed as a whole. I still think there are some great and innovative projects that had a successful ICO in the last 2 years. So I wouldn't generalize and say that ICOs are all bad but yes, you are right, there were a lot of scam-ICOs.
That is the main reason why investments by public are not as active as they use to; you could always just get it at a lower price after the ico. However I think if a project delivers on a product and start generating traction that sentiment could change.