Ray Franz said that the GB members did very little ministry (ISOCF P200).
Just my limited experience - there was a vacation home in my territory that the owner would only rent out to "higher-ups" in the Org as a freebie. Basically the more senior you were - the more chance you would have to stay there. So there were prominent JWs from all over the world - Construction Overseers , Regional Overseers , Branch committee members , Bethel Heavies- a Who's Who of JW top brass. I was a keyholder and myself and my wife would often clean it so we often would meet the occupants , who usually stayed for a week. Somewhat optimistically , the meeting times and field service times and locations were pinned up on a notice board inside. Occasionally they would turn up for a meeting (KH was only 10 minutes drive away. ) NEVER did anyone ever go to a scheduled field ministry arrangement. NEVER.
Regularly on meeting up I would ask them if they wanted to go out for an hour doing a few RVs close by and often my wife would ask the sister if she wanted to go on calls or a bible study. I supposed I had an assumption that as "spiritual people" they might want to do an hour on the ministry locally during the week. Virtually every single time the offers were kindly refused - I can honestly only think of a couple of occasions ( over 10 years ) that someone went on a study with my wife ( and the property was occupied almost every week of the year).
I actually mentioned this to the elders who visited me after I faded and one of them was honest enough to admit that it was something that really stumbled him as well.
I know these people were on vacation and the Society gave them very little time off but it does show the attitude towards field ministry by the higher ups in the Society that I would assume is mirrored by the GB.