IMO,Brokeback was a very important moment in their lives,important enough as to change them forever.But I think that any other place or circumstance that had allowed some degree of intimacy or,at least,allowed them to work together shoulder to shoulder,had developed an intense relationship between them.Because they were two uprooted country boys who needed above all some love and tenderness,someone who makes them feel all the important human beings that nobody had made them feel before,neither their own parents.Remember how powerful and strong Ennis felt in s.s. when they went up to the sheep after having shared some conversation moments with Jack;it was just because at the end he had found someone who cared for him,who believed that his opinions and wishes were important by themselves...In this sense,then,I think that any other place could have became their "happy Arcadia" and their shelter before society,no matter if it had been a house,a saloon or a city's street.
However,it's true that the mountain beauty and greatness added a factor of freedom to their relationship; they were alone,in the middle of nowhere,taking care and being cared of and from each other,and,more than in any other place,they could be
themselves,as they were and felt. Loneliness in all senses,both physical and psychical,created some bonds that it was easy that could grow up until being eternal.But I guess that when Jack says "Ol' Brokeback got us good" means that this place or wherever they had met,changed their lives forever because,simply,was the first place they really know each other in all senses.That these times of shared loneliness had made them fall in love with each other as they wouldn't had though before.That he realised Ennis loved him when they were talking about how much they had missed one another during these four !@#$ years and he wasn't able to tell anything,but everything his reaction speaks volumes-his eyes are full with tears when he just remembers how his life has been without Jack,what is very significant...-.I think,in sum,that when a love is so great as theirs,any place can be your own Brokeback...
