How long should a successful rebuild take?

I don't believe all rebuilds are created equally. Sometimes teams find themselves needing an overhaul and have a plethora of resources to do so. Other teams may have spent those resources trying to re-tool and/or extend past success. It all comes down to the starting line a team is beginning at, as well as what kind of young core it has built in to build around. Teams who have pushed their starting line way back will have a longer way to go. Unless a team gets really luckky, correcting financial matters doesn't happen quickly.