Bedrockgames
I post in the voice of Christopher Walken
I find this to be a highly theoretical objection, at best. I say this because I have not witnessed a situation like this in an actual game. I mean, yes, 2 players agendas could simply be mutually exclusive, but it is actually pretty HARD to arrange that, unless each player is very specific in what they declare as an agenda/goal, and then they would almost have to arrange for this to be a problem (IE if I claimed my PC must destroy the Book of Eibon and you claimed your PC must own the Book of Eibon). You almost have to contrive something like that. Plus I'm not super convinced this would create an actual problem in play, because the conflict would surely drive a lot of story!
Both of those goals are perfectly possible for players to declare in a traditional game too. So I don't think that example illuminates the issue (I can decide my character must destroy the book fo Eibon).