In my own experience it's a matter of only having that much time in the day. For 7 years I had somewhere between 20-25 people I was directly or indirectly responsible for. There was just not enough time to get anything useful done in the code and my time was much better spent solving problems that others couldn't. A few times I was able to pick up some really simple change just to get the experience first hand to go through all our processes and see where we can do better.

I always kept coding nights and weekends but it's just not the same and over time you are gonna get a little rusty. That said I greatly enjoyed getting my hand dirty all day during a sabbatical I'm taking.