It's because they have serious responsibilities,
bullying shepherding the flock in their care. They have all those publishers to spy on watch over, and they still have to find them to earn a living and look after their own families.
I think dedpoet sums it up here. My dad is an elder and PO (I think - I don't ask too many questions they might think I'm still interested) and he rarely has a night off a week. He is always out lamb bashing as my mum calls it. On top of this he goes to mid week field service ferries numerous lazy arses around in his spiritual vehicle, goes off giving talks, aux pioneers, has a couple of bible studies, helps with the new build and putting up bros and puts up the CO every single time he visits and somehow earns a crust for him and wifey - there really is not much left, no wonder he hardly cracks a smile poor old sod what a waste of a life!