every case has its specifics, but one thing about this sentence...Are men just more naturally loners, whereas women are always "networking" with friendships all over the place? Maybe that's the problem? I dunno.
a man who suddenly doesn't 'have' anything, will create anything else in order to survive. and usually he will survive. it is the nature of males.
a woman who suddenly doesn't have anything... well... they're lost. and they will require that 'network' as you call it, in order to bring them back.
men will not perish, network or no network. look at african and s-am tribespeople. sometimes entire tribes are extinct but the last remaining member is always a man [+maybe a dog!] women without a network... is something i think everyone could agree, is 99%+ a disaster. in fact i'd be very wary of a girl who doesn't have a network !

so imo they build and maintain them because, just how providing and creating is our purpose, maintaining and securing is theirs.