There are also the trust, responsibility and activity factors.
I'm not saying Khal isn't qualified, but he hasn't gone through the months of staff testing like divinity did.
You really do need this role to be fulfilled by someone who is 1000000% trusted, for the sake of your own protection.
All it takes is one greedy / corrupt SDN manager to destroy OSB forever.
Also there's the financial aspect, is there even money for another SDN manager?
I understand your frustration though, it probably wouldn't be a bad idea to train a junior manager for the future, but you can't just expect them to hire someone out of the blue.