To play devils advocate, there could be those who are quite happy to settle in an area and school their kids without having to up sticks every 2 years. Wife could get a job and make up the difference. Could even be tax efficient if one remained just below 40% threshold.
Meanwhile, all the career knobbers could carry on working stupid hours, disappearing up their own jacksies doing secondary duties etc. What that option doesn't solve is the accountability of someone who comes in and screws everyone over for 2 years to make him/herself look good and leaves a goat for the next poor sucker to take over.