exactly! I always have preached underdrive pulley's no longer are worth it. The A/C and alternator are already disengaged under large throttle which means the only thing that is underdriven is power-steering and engine cooling. The two things I would never want to have heat up more than normal.
In older cars it was more worth it because you had all 4 systems sucking power but in new bimmers, you only have the water pump and power steering sucking power.
I hope with newer engines they go with electrical water pump like the N52 engine. That way it would completely eliminate the need for an underdrive pulley. Especially if they go electric steering which they will.
Actually may eliminate the need for a accessory drive if they can change how the A/C is run.
This would probably free up 15-20 hp consistently in cars and save on mileage. That is a win-win and should be the focus for bmw on m cars rather than going turbo.
Lighter cars and elimination of parastic losses and direct injection could have netted great mileage on naturally aspirated high revving cars to meet both mileage and enthusiast desires