I would imagine the axle could be turned and sleeved but could it then be sold cheap enough that they would sell?
I don't know what margins look like in the auto parts business, but if the new axle I just bought for $129 cost the supplier $99 and the manufacturer $65ish I'm thinking it would be hard to repair an axle cheap enough to save the consumer any money.
On the other hand, there is a machine shop locally that is hiring blind machinist for about $15/hour. Maybe you could keep cost of materials under $15 and turn them out faster than one each hour.
So I'm postulating a repaired axle for maybe $70 against a new one for $130. I'd probably still choose the new, but maybe other people would choose the rebuilt...
I told my son the bad axle will soon be bolted to an old brake drum or wheel, and with a plate mounted on the differential end, the axle will become a grinder stand.
Do you suppose I can sell those at a profit?