Carlos, to the best of knowledge, that this is true in every US jurisdiction, certainly the ones I know. This is fairly standard stuff. If it's not true in any state, it's probably because they don't have member non-profits in their statute, and not because they place members in a relatively lesser position vis a vis the Board. (Caveat: I have not done a 50 state survey on this, I'm not admitted to the California bar, and this is not a legal opinion.)
Nigel, in the US, Members would not be considered "owners" of a public benefit corporation or similar non-profit. Generally speaking, non-profits cannot be owned (there are some exceptions in some states, but they are narrow, e.g., a non-profit may have a non-profit subsidiary in some states, but the parent non-profit still can't be owned). I* would take from that that Members do not have a property interest in the public benefit corporation. Their power does not come from property. It comes from the powers given to Members by the statute of the relevant jurisdiction. (There is something called a "mutual benefit" corporation, which benefits only its members, where the analysis might be different. Since ICANN is clearly not one, I will eschew the rabbit hole.)
Greg