In my experience, process is to make things predictable, not efficient. Nothing scares a middle manager more than having to say "I don't know". They'd much rather say "this will take my team 8 months" than "this will take between 3 weeks and 6 months to complete".
I suspect one of the reasons things become more predictable is that overheads start to dominate the time it takes to do things, and overheads seems to be much more predictable.
In my experience, process is to make things predictable, not efficient. Nothing scares a middle manager more than having to say "I don't know". They'd much rather say "this will take my team 8 months" than "this will take between 3 weeks and 6 months to complete".