Because "NATO" is a fiction, and it will not take much to have it formally dissolved.
The members of NATO, for diverse reasons, will prefer to maintain the fiction, which is certain to crumble with the first rifle shot - so they dare not put their fingers near a trigger.
I don't see NATO so much as a fiction as it's an organization that has a military with a changed purpose.
It was obvious with the outrageous US/NATO bombing in Libya "to protect the defeated rebels so they could safely return home". Instead, Libya was destroyed and disasterous attempts to install a functioning pro-west gov have been a disaster. Khaddafi's billions were not (as threatened) removed from Italian banks which would've been an economic nightmare for Europe. And now Ukraine gets the NATO treatment as Russia makes alliances to have a currency independent of European and US bankers? hmmmm......
NATO's military has become the military that does the bidding of EU/globalist-banker interests. It isn't protecting Europe from being over-run by enemy forces any more than the US military is protecting us.
Civilization, according to the global elite's definition, will survive. The only problem is they're defining what's worth surviving as a very small, very powerful, very rich entity that would just as soon "cull the herd" as they consolidate their status. The bad news is we're all part of the herd.
I used to think this whole Illuminati-secret globalist masters thing was conspiracy. Now I suspect it's the hidden history of civilization.