It would if we really were waiting on the land. We automate so much around the process that it doesn't have to be watched closely. Most of the time a diff is fire-and forget and when it fails or breaks something our tooling will notify us.
We also ship with what we call "stacks" which are sequences of dependent diffs, so if you really really have to have one diff land after another they can both be "landed" without the possibility of racing each other