You are right, Ronnie. In the past, a consigliere was elected by all the members which was essential because of the fact that he was meant to be a counselor to all members and a spokesman for them in front of the boss. In this day and age, when a gathering of 200 plus mafia members taking a vote can easily be interrupted by LE, I think the Families have adopted another way of electing the consigliere. However, I do not think that the boss, and only him, is appointing the consigliere. That would be undermining the soldiers and captains trust with the consigliere who is the one who is designated to represent their interests. I think today, especially with the bigger Families, the consigliere is appointed by the administration and a number of captains.

John Gotti was full aware of the traditional way of electing a consigliere. He was once caught talking to Joe N Gallo, threatening him with demotion if Gallo wasn´t going to accept Gotti´s takeover. Gotti said that he could easily replace all the captains in the Family by his men and that these captains would then have a vote of replacing Gallo with a new consigliere more to Gotti´s liking.

Gravano never talks about the traditional way of electing a consigliere. Most likely because he had overlooked this important tool of keeping the power balance within the Family. Or perhaps he never fully understood it himself, amazing considering he served as an acting consigliere for a couple of years.
In his testimonies, Massino doesn´t mention the traditional process of electing consiglieres either. I don´t think that he was ever asked about it which is a shame in my opinion. Every Mafia buff and every Mafia watcher who is interested in this aspect of the traditional way of running a Family, I´m sure, agrees with me.