I don't think I would exactly call these men "monks". It has been pretty normal throughout history for a fairly large proportion of men, especially those lower down the economic ladder, to be permanently single or not marry until pretty late in life. These days, they don't have to work as much to avoid complete destitution or starvation, they're not as likely to die young, and they've largely replaced visiting cheap prostitutes with gooning, but otherwise this is not any unprecedented phenomenon.

It does mean that the economic growth that allowed most men to be a plausible marriage partner in the mid-20th century no longer obtains, which is a bad thing, despite the small comfort of consumer goods being cheap enough to alleviate some of this pain.