Some are from the get go, but others just fail for other reasons. Try to research about it as much as you can. It's a case by case issue.
When researching them, read the white paper carefully, find out who is advising them, who is backing them, who is endorsing them, and how transparent they themselves are in terms of identifying themselves, their background, the team, etc.
All this should boost your confidence in the ICO, although as with all startups the risk(s) are higher, but so are the payouts for the initial investors.
Case in Point: Look at Latium (LATX). They have a great concept/idea, will be 'working' the cryptocurrency they are issuing, the more they can circulate the currency that greater value it will have. Then look who their advisor/endorser is, John McAfree - that's huge! If he's in and he's endorsing them (I'm sure he's investing in them as well). So, all this to say that you don't have to get into an ICO on a wing and a prayer, even though there are risks as with all venture capital, still you can mitigate some of the risk by reading as much as you can.
Here is a link to Latium, the example I cited above:
https://latium.org/welcome/mfchiro -- will give you an good example of an ICO that is legit.
