Overworked teachers..?

I've heard plenty of teachers complain about the amount of planning they need to do, and the amount of time they spend marking.

My wife is a teacher, I know it's not the half days and masses of holidays it's generally perceived to be.  It's a job that does actually consume a huge amount of time.  Would I swap my 9 to 5.30pm job, with just 5 weeks holiday?  No, I've got a much better work/life balance.

As a kid at school I was told to work on my own and not copy from others.  Has this mentality continued through in to the teaching profession?

Successful companies can't succeed by paying different members of staff to sit in isolation and repeatedly do the same bit of work as everyone else.  We have one person do one particular job and we all try and benefit from each other.  We're all cogs in a big efficient machine.

Is it like that in education?

How many teachers actually cooperate with other teachers and share the planning?   How many schools have set up a central repository where all the lesson plans can be stored, shared and re-used?

Going up a level, how many schools share their planning with other schools?  

If we're going to have an improved and consistent level of education, isn't this where we need to aim to get to?