Is the age of monastic life over? Is it societal conditioning or keeping up with the times?
This series of questions is quite involved and surely a book could be written to properly assess the status of how well a very traditional monastic community is holding up in modern times. 

But a few things did come to mind that can be easily stated. Your comments are from people who are not currently part of the monastic tradition. They've made their decision and had their reasons. But the monastic community is alive and well without those individuals. It's far more interesting to hear the perspective of those actively a part of the monastic community.


  The bar is quite high for someone in the west or in any westernized country really, to forsake all known things, and head off to the other side of the world to become a monk.


I suppose that's true. And yet people do it and stick with it and find it to be a meaningful way to live. As far as forsaking material things, an interesting example of this is Ajahn Siripanno. His father is a billionaire and he could have lived a life of extraordinary wealth and privilege. And he choose to ordain as a Theravada monk instead. That's a powerful statement about priority when people see clearly. 


  Now, a monk who isn't a local, enrolling in any foreign tradition spends a lot of time learning the new culture, the language, the food, the social mores, often dealing with racism to boot - all of which appear to be a waste of time, taking away from actual time spent on spiritual development.


The head monk are our local Theravada monastery, originally from Laos, does not speak English despite having been in the US for a number of years now. Bilingual lay followers at the temple have told me his reason for not doing so is so that he will have fewer distractions. I think this is a smart approach really. Of course, he is not in a position of having to actively seek out lay followers, it's an ethnic community which seeks out the monastery. But that's certainly one way of avoiding the waste of time you speak of. 

As far as whether we are moving towards some sort of a "permanent" secularization in society, that would be short sighted speculation. Throughout history, societies have changed and become more or less religious. Religious traditions have become corrupted and then reformed. Religious traditions become more heavily focused on one aspect over another and additional sects emerge (I think this latter is roughly how the "forest traditions" revived in modern times.)

It's not for everyone. But I would think for those "with little dust in their eyes" monastic life will survive all that modern life can throw at it. :)