I just wanted to comment on this by saying: The lore doesnt have to make sense in a "logical" or carefully planned way. Thats not how societies and specially traditions work. If the Viis (and the Viera) have lived like this for thousands of years they're not gonna suddenly change their fundamental way of living because it "makes no sense (anymore)". Considering how long they live we can also assume that at least part of the living population was born and raised before the flood of light (or the Garlean Invasion on the Source) and they'd be even more kean on keeping the old ways of living.
Traditions arent always based on what makes sense right now but more on what made sense at the time. I'm trying to think of any good real world examples, but I cant come up with any that dont have the potential to just blow up with politic or religion. So let me try one that isnt 100% fitting but less... explosive: I watched a japanese documentary a while ago and a sushi chef explained the way he was cutting a type of eel. The way he cut it was from the eels back not the belly, which is a bad and difficult way to cut this fish. The reason? He was honoring samurai tradition, specially Seppuku. It made no sense for him to cut the eel this way, except for an old tradition. Again, not the best example probably since its less severe than risking a whole population to vanish, but I hope it brings accross the point I'm trying to make: Traditions dont have to make sense and they arent as quick to change.
...and even if they were, lets think about this for a second: What would happen if the male Viis just returned to the village for good? They lived as lone wolves for decades so they're probably not a very social lot. We would have the new problem of suddenly having a bunch of warriors who are used to being alone and always ready to strike to protect the forest being turned into housewives (by your suggetions) - how is that gonna work?
It might not be not "logical" that they male Viis are still staying outside of the village and are hidden in the forest, but its "natural" and a believeable lore as far as I'm concerned. Way more believable than suddenly turning them into housewives because their old ways dont make sense anymore and the society was changed over night.
...even though the real reasons are obviously that they probably wanted to stay close to the Viera-lore from Ivalice aswell as not having the time and ressources to model/design male Viera. But even if they had: If they wanted to keep true to the Ivalice-lore, the male bunnies are out in the forest. And societies dont always do what would be best for them or whats the most sensible way - sometimes they stick to traditions because "thats how its always been!" even if thats harmful. The Viera/Viis are pretty realistic in that regard.