It goes to zero it's mean no one using it.
So those ICO would go to zero first to cause ETH go to zero
I think you don't know about ico , here no discussion about the ICO .
well here the matter of the ETH whether to go zero will be useless or not .
If you can think dear OP that everything in this world has own value ( may not for all but for particular persons ) Then why we should consider ETH= nothing or value zero .
Since probability of coming the price of the ETH to be zero is impossible but think if it became zero then you will get loss only like a dead coins , because there are many coins which starts at 1000 to 2000 in the starting but after the week they get to 1 Satoshi which is equal to zero value because no one will buy .
Now here I already got many loss in the trading that after buy the price get to 1 Satoshi for ever like asafe , alien , Eva at the yobits.
About 0.1btc loss in these coins , so I think everyone will get stopp once for some days after the shock of 2-3 days they will start again with new one .