There's an interesting thread here analyzing ICOs as if they were startups. I'll give the counterpoint: they're investment scams.
Investment scams are big business! $5 billion+ a year in the US. But they receive substantial adversarial attention from regulators.
Scammer problems: you have to recruit marks, successfully transfer their money to a scam vehicle, exfiltrate, and avoid arrest.
Recruitment in traditional scams happens over phone calls (boiler rooms), letters, and every other channel people talk to each other on.
The fundamental innovation of crytocurrency is that it has distributed, self-organizing recruitment through incentive structure for adoptees
Now how do you get money into the scam vehicle? Material amounts of money start in the traditional financial system. This is tricky for you.
As a scammer, you can't just tell Milli Smith to take out a reverse mortgage and wire $800k to an account in the Caymans. Her bank says No.
So your options are e.g. suborning a listed company and wearing it like a skin suit, then having marks purchase shares of that company.
This is dreadfully inconvenient, because marks might not have brokerage accounts, and scaling the scam gets it shut down quickly.
Enter the cryptocurrency ecosystem, which needs one node with plausible deniability and a bank uplink. Controls of other nodes irrelevant.
The cryptocurrency ecosystem has what strikes participants as a surprising difficulty in maintaining one node with a foot in real finance.
This is not surprising because that node's economic justification for existing looks a whole lot like money laundering at scale.
Now for whatever reason this shell game is really successful, and after value is in cryptocurrency ecosystem, it flows from scam to scam.
Exfiltration! How do you justify to the grownup financial system where your $20 million came from? You can't say "Defrauding Milly."
So instead you say "Speculation.", which is just enough for the see-no-evil gatekeepers.
Now how do you avoid going to jail for it? The plan appears to be "Exploit regulatory ambiguity and move as fast as possible."
With varying level of "Make some sort of plausible excuse that there does exist an actual enterprise and it is not just scams all way down."
Economic substance is not a novel innovation for scams. Sometimes e.g. the boiler rooms did pump stocks for companies which had products.
Small company which makes pool cleaners: a possibly high risk investment. Same company implying 1000X returns: scam scam scammity scam.
Here again we see the fundamental innovation of cryptocurrency, where the central actors can mostly truthfully claim to have never said it.