Why not use drones to repair attack drones in Oblivion?

If one stretched oneself, one could reason this out like so:

1. Jack and Victoria are being used just like drones. Their minds are wiped and they are programmed to do their jobs.
2. The dexterity of human hands and our ability to reason is a huge plus over the drones. Couple this with the emotional motivation provided to Jack that he's battling against the Scavs who have destroyed his planet and you could say that you have an efficient team.
3. The humans are not necessarily only maintaining the drones. They are also maintaining all the planet-sucking machinery as well.
4. The Tet is unaware of Jack's flashbacks. It doesn't know that the mind-wipe was not perfect.
5. Lastly, what is Tet going to do with all the remaining Jack-clones from the war? Reprogram them and send them out into the field.

If somebody could get their hands on the original comic, more could be explained.

They did have the technology but then who would fix the repair drones?...It could be that the 'scavs' would just shoot down a drone and bait a repair drone so they can ambush it and shoot that down...and so on. If you have a human being, he can get killed and replaced much more easily I think than building a new repair drone (genetics takes care of engineering and growth as opposed to getting supplies and manufacturing each drone.

Also, humans can heal over time if they are injured. They can reason and make plans and use tactics to engage the enemy instead of just flying in guns blazing. And they don't need to 'scan' a location to know somebody's there, their recognition of hostiles is instantaneous and doesn't blatantly give them away in their environment (like the drone's bright scanning light).

I would assume that since it was nothing to replace Jack...they needed the Human factor to get the job done since other limitations could arise. Also, because Cruz lends to making this a great story.