Most Hondas and Chryslers have vacuum actuated AC controls so there's a lot of cars on the road with vacuum AC controls.
BMW manages to have electric locks and a locking fuel filler so that's not what prevents MB from 'moving on.'
With all the other electric controls on an MB door, a couple more wires and a solenoid for electric locks cannot be a big deal.
My issue with vacuum locks is that when rear seat passengers open a door when the system is locked, it feels like something is being forced to allow the door to open. Also, that door lock can't seem to decide whether to stay open or join the other in being locked when the door handle is released.