The trusted setup only requires one person to not collude. Given how skeptical Peter Todd has been about this entire business, I'd be t that at the very minimum he was honest in his role.
As someone entirely unfamiliar, why only six? If the weakness is all of them colluding, then wouldn't adding anybody in the world (let's say, me) as a seventh make it strictly better?
The protocol is expensive; it took 2 days with 6 people. After a certain point, it's not practical to add more participants without increasing risk. It requires gigabytes worth of communication per participant and many millions of curve operations.
