My point was that OS dispatchers don't spend time working out how long things will take to compute, to allocate resources (such as CPU time) properly into the future; what they do instead is they just put the stuff to compute into a dispatch queue and go from there. Then if it's a novel thing or million times repeated thing doesn't really matter.

BTW, one indication that Scrum is bad is that nobody is doing its analogue (syncing everybody once a day?) in computing. Sane project management practices should be universal, and should also work for operating system schedulers.