I haven't been watching this season (mainly because of American Idol, but I've read a lot about it, so I'll add my two cents:

Both sides seem to have fractured -- the women along the age divide, the men along the strength one -- but the men made the more fatal mistakes. There were two, in particular. The first occurred when Colton came up with the stupid idea to give up Immunity to the women and go to Tribal Council to get rid of Bill (and Leif was probably the decoy used to blindside Bill). It had to be a unanimous vote, so if even one man said no, the women would have gone. Of course, Colton would've made the dissenter pay at the next Tribal Council both attended unless the dissenter got some support, but still the men would have maintained a lead on the women.

The second seems to have occurred after the merge when the men failed to band together and try to get rid of the one woman most likely to resurrect the all-girl alliance: Alicia. Instead, guys like Troyzan and Jay joined forces with the women to get rid of Jonas. That error was compounded by Troyzan's erroneous decision to trust Kim as well as Kim's very smart gameplay. Now, they're on the verge of being Pagonged and they will be unless the women become like the ones in Vanuatu.