That's gross oversimplification. In some models, some managers are pure resource managers as you're describing. A lot of us are functional managers, though. I own the outcome.
It's become really common in engineering, particularly in orgs doing agile, to split resource and functional management. I don't care for that. I spent a long time as a product owner and wondered quite often why I couldn't just absorb the resource manager's responsibilities as well, since the only thing I wasn't doing was writing reviews. Every other problem rolled up to me, since I was accountable for the outcome.
It's become really common in engineering, particularly in orgs doing agile, to split resource and functional management. I don't care for that. I spent a long time as a product owner and wondered quite often why I couldn't just absorb the resource manager's responsibilities as well, since the only thing I wasn't doing was writing reviews. Every other problem rolled up to me, since I was accountable for the outcome.