Gender locked race?

[Jaywalker]

Let me rephrase: What possible reason would they have to create the lore that male Viera are incredibly few in number and never leave the forest, while they're simultaneously working on creating Viera as a playable race?

Tbh I think it could be an interesting storytelling conflict. Motive-wise, viera lead a pretty tough and limited lifestyle. It wouldn't be crazy to think any of them, including males, might want to leave that for more lifestyle freedom. If the males especially are predominantly fighters, boom. That's a skill they can use to support themselves as adventurers. But with all of this, if there's a limited number of males and they've been fighting off Garlemald to protect the forest and a bunch of viera are leaving the forest behind for a slew of reasons, that creates first some stigma for any player character viera who have left (especially males since there are less) and with it juicy conflict. Also possibly places strain on viera traditions and gender roles, like they might need to send female Viera to defend the forest too.

Not to mention this encourages them to start breeding like rabbits to replenish ranks. ;P

The male/female extreme divide can be used to justify having villages of entirely female or male viera, to maintain continuity with FFXII, to offer further immersion into alternative societies, you name it. Originally in FFXII I suspect it was to make less models to design and just have a bunch of sexy bunny girls, but moving forward it strikes me as more of a nod back but with some wiggle room.

They put themselves in an interesting position where they conceivably could delay male viera release, or technically avoid it (although I think that wouldn't go over well) but they could also work them in no problem. What might be interesting is if they have conditional release, like you unlock male viera in the character creator if you complete xyz quests. There's flexibility atm.