For one, we don't know how long Ogres live in this setting. It's quite possible that they're very long lived, which would mean that even one surviving for any length of time would mean that the species could keep coming back.
For two, Ogres are monstrously strong. They're one of the top tier units for a reason. It takes a lot of effort to down a single Ogre that reaches max level in the dungeon... and those are, from what I understand, basically just grunts. Ogre Chieftains like the one the MC strikes a deal with to begin with are likely much more powerful and likely require absurd amounts of effort to take down. Given the nature of humanity and politics in general and all that, it's not surprising that no one actually bothers to take on that sort of monumental effort unless they absolutely have too.
As for the succubus powder, the Doc explains all too well why they can't do that. One, the stuff is too rare. Two, women that aren't strong enough suffer through a variety of side effects. Three, the resulting spawn has their life span reduced drastically. Basically, it takes exceptional women to use it in the first place, and then, even if you DO use it, the things you make with it won't live very long. Useful for some disposable elite minions, useless if you need a long-standing army. Most species also wouldn't agree to have their children's lives shortened like that, which is likely why you can only use goblins and not slimes or ropers to make elite versions of those.
Also, a number of the things that are used as units don't even use the kidnapped women for breeding. For liches and Archdemons, the women in question are quite literally sacrificed in the literal sense. For the Archdemons in particular, they're drained of all their blood as virgins if my memory isn't failing me... and the description kind of implies that the girls are, y'know, not dead during the process, but rather, it's the process that kills them.
So yeah... if you REALLY look at the details, the MC is quite the monster for allowing all that to happen. The Chaos goddess is no purveyor of sunshine and rainbows, that's for sure. You are absolutely playing a total bad guy in this one... Not that the fates of the named girls are, y'know, exactly ok either. Most of them basically have their minds completely destroyed and replaced with something else made out of the pieces. Outside of Lynn, who's in a league of her own when it comes to mental strength, and Reina, who doesn't need to be corrupted, all the other girls essentially suffer identity death. Well, in two cases, it's pretty literal with no ifs, ands, or buts about it.