Thanks for the replies. Despite what you might have come to expect from the internet, and STW in particular, not everyone who asks a question is trying to provoke an argument.
I’m interested in learning new stuff, even if it’s about stuff I’m not interested in.
I guess I was thinking of how I used to play for the school rugby team.
The PE teacher was the coach, picking the team and choosing tactics.
I was thinking of a football manager as a sort of headmaster, making sure we had a changing room and that the grass got cut, but not actually involved the details of how the game was played.
Or, to use the welding analogy again, most workshop managers wouldn’t know the difference between a MIG welder and a TIG welder. It’s better that they just allocate a budget to someone who does.